https://www.khanacademy.org/science/middle-school-earth-and-space-science/x87d03b443efbea0a:earth-in-space/x87d03b443efbea0a:the-solar-system/v/the-solar-system-ms 2024-01-04T21:44:22.995765104Z The solar system Our solar system, formed from a nebula, consists of the sun, eight planets, asteroids, and comets. The inner planets, Mercury, Venus, Earth, and Mars, are rocky, while the outer planets, Jupiter, Saturn, Uranus, and Neptune, are gas giants. The asteroid belt separates these two groups, and the Oort cloud, filled with comets, lies beyond Neptune. Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/b8fab4c8-cc6b-4c1c-808c-ae49dbbe513d_1280_720_base.png The solar system Our solar system, formed from a nebula, consists of the sun, eight planets, asteroids, and comets. The inner planets, Mercury, Venus, Earth, and Mars, are rocky, while the outer planets, Jupiter, Saturn, Uranus, and Neptune, are gas giants. The asteroid belt separates these two groups, and the Oort cloud, filled with comets, lies beyond Neptune. https://cdn.kastatic.org/ka-youtube-converted/wTyqO-tfs7Q.mp4/wTyqO-tfs7Q.mp4 296 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/middle-school-earth-and-space-science/x87d03b443efbea0a:earth-in-space/x87d03b443efbea0a:the-solar-system/e/understand-the-solar-system 2025-06-18T15:00:50.065121331Z Understand: the solar system Check your understanding of the solar system in this set of free practice questions aligned to NGSS standards. Lauren Rosebrugh exercise https://www.khanacademy.org/science/ap-college-environmental-science/x0b0e430a38ebd23f:global-change/x0b0e430a38ebd23f:greenhouse-effect/v/greenhouse-effect-and-greenhouse-gases 2024-06-28T21:00:15.59562973Z Greenhouse effect and greenhouse gases The greenhouse effect, driven by gases like carbon dioxide, methane, and water vapor, is essential for maintaining Earth's habitable temperatures. However, excessive concentrations of these gases—particularly due to human activities—can lead to global warming and climate change. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/27e417aa-bb45-422d-bb99-7e0e28da1250_1280_720_base.png Greenhouse effect and greenhouse gases The greenhouse effect, driven by gases like carbon dioxide, methane, and water vapor, is essential for maintaining Earth's habitable temperatures. However, excessive concentrations of these gases—particularly due to human activities—can lead to global warming and climate change. https://cdn.kastatic.org/ka-youtube-converted/YpfxiDktSoI.mp4/YpfxiDktSoI.mp4 419 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/ap-college-environmental-science/x0b0e430a38ebd23f:global-change/x0b0e430a38ebd23f:greenhouse-effect/e/greenhouse-effect 2025-12-18T00:30:56.558401705Z Greenhouse effect Apply your understanding of greenhouse effect in this set of free practice questions aligned to AP standards. exercise https://www.khanacademy.org/science/ncert-class-8-science/x55541eeaec8b3a9a:our-home-earth-a-unique-life-sustaining-planet/x55541eeaec8b3a9a:what-makes-earth-suitable-for-life/v/what-makes-earth-suitable-for-life 2025-10-03T04:00:55.279024297Z What Makes Earth Suitable for life Why is Earth the only planet we know that supports such rich life? 🌍 In this video, we explore the “just right” conditions that make our planet special. Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw What Makes Earth Suitable for life Why is Earth the only planet we know that supports such rich life? 🌍 In this video, we explore the “just right” conditions that make our planet special. https://cdn.kastatic.org/ka-youtube-converted/WTJMk4t6c2Q.mp4/WTJMk4t6c2Q.mp4 247 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/ncert-class-8-science/x55541eeaec8b3a9a:our-home-earth-a-unique-life-sustaining-planet/x55541eeaec8b3a9a:what-makes-earth-suitable-for-life/v/why-earth-is-unique 2025-10-03T04:00:55.279024297Z Why Earth is unique Why is Earth so unique? And here’s a bigger puzzle: if Mercury is closest to the Sun, why is Venus the hottest planet? Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Why Earth is unique Why is Earth so unique? And here’s a bigger puzzle: if Mercury is closest to the Sun, why is Venus the hottest planet? https://cdn.kastatic.org/ka-youtube-converted/t8A_6GrDgAg.mp4/t8A_6GrDgAg.mp4 397 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/strengthened-shs-earth-and-space-science-1/x006d5d274c051fd7:origin-and-structure-of-the-earth/x006d5d274c051fd7:earth-s-place-in-the-solar-system/e/what-allows-life-to-be-sustained 2026-04-07T22:23:57.656416987Z What allows life to be sustained? Explore how air, water, soil, sunlight, plants, animals, and balance among Earth systems work together to sustain life on our planet. Yajurva Joshi exercise https://www.khanacademy.org/science/ncert-class-8-science/x55541eeaec8b3a9a:our-home-earth-a-unique-life-sustaining-planet/x55541eeaec8b3a9a:what-makes-earth-suitable-for-life/e/what-makes-earth-suitable-for-life 2026-04-06T02:41:58.374508961Z What makes earth suitable for life? Explore why Earth is the only planet that sustains life — its right position, size, atmosphere, and magnetic shield — through engaging recall, understanding, and application questions. Yajurva Joshi exercise https://www.khanacademy.org/science/in-in-class-10-biology/in-in-reproduction/in-in-asexual-reproduction-and-its-types/v/fission-binary-multiple-with-examples-how-do-organisms-reproduce-biology-khan-academy 2020-08-28T13:57:05Z Fission (binary & multiple) with examples Let's explore binary & multiple fission with examples. Mahesh Shenoy video https://cdn.kastatic.org/googleusercontent/F9agOVf8O4VArm8GPCrX3FUfDxUJ0vUnYLJM2_ePWf2TTABQSJs9F-VLOvEE3QDckYvDh2bJzbpDmtcSboDmh0vZrw Fission (binary & multiple) with examples Let's explore binary & multiple fission with examples. https://cdn.kastatic.org/ka-youtube-converted/D3FN3jLlT54.mp4/D3FN3jLlT54.mp4 586 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/ka-biology-grade-12/x406cf103e0507862:sexual-reproduction-in-flowering-plants/x406cf103e0507862:pollination-and-double-fertilization/v/types-of-pollination-in 2025-03-04T07:03:01.189124034Z Types of Pollination Pollination results in the beautiful union (Greek word "gamy") of male and female gametes in angiosperms. Watch this video to learn about the different types or kinds of pollination observed in nature. Nivedhitha Suresh video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Types of Pollination Pollination results in the beautiful union (Greek word "gamy") of male and female gametes in angiosperms. Watch this video to learn about the different types or kinds of pollination observed in nature. https://cdn.kastatic.org/ka-youtube-converted/cd_dCws1hG0.mp4/cd_dCws1hG0.mp4 612 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/in-in-class-10-biology/in-in-reproduction/in-in-sexual-reproduction-in-plants/v/fertilisation-zygote-embryo-germination-how-do-organisms-reproduce-biology-khan-academy 2020-06-23T07:22:42Z Fertilisation, zygote, embryo, germination Let's explore how fertilisation takes place in flowers. Mahesh Shenoy video https://cdn.kastatic.org/googleusercontent/GwFFvyYffU15WmjJ7Q2eKa0o4ZuE-UZu9jDYnATJxOdZCME-F8Dff_sEDG_wrp7IxK5SbTbJ66Ha6vyfRYYByfy8 Fertilisation, zygote, embryo, germination Let's explore how fertilisation takes place in flowers. https://cdn.kastatic.org/ka-youtube-converted/y-emlY6DBH8.mp4/y-emlY6DBH8.mp4 768 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/bridge-course-class-10th-science/x37589313f9a4c197:week-3/x37589313f9a4c197:how-do-organisms-reproduce/e/asexual-reproduction 2026-04-10T12:00:44.946307725Z Asexual reproduction Let's solve some questions on asexual reproduction Vibhor Pandey exercise https://www.khanacademy.org/science/in-in-class-10-biology/in-in-reproduction/in-in-sexual-reproduction-in-plants/e/in-in-pollination-and-fertilisation-in-plants 2026-03-06T17:50:38.494926415Z Pollination and fertilisation in plants This exercise provides practice for high school level concepts of pollination and fertilisation. saiyem exercise https://www.khanacademy.org/science/jnv-board-preparation-class-12-biology/x54e191b2bf661780:week-1/x54e191b2bf661780:sexual-reproduction-in-flowering-plants/e/sexual-reproduction-in-flowering-plants-boards 2026-04-07T22:23:57.656416987Z Sexual Reproduction in Flowering Plants This exercise tests knowledge of the unit Sexual Reproduction in Flowering Plants Nivedhitha exercise https://www.khanacademy.org/science/bridge-course-class-10th-science/x37589313f9a4c197:week-3/x37589313f9a4c197:how-do-organisms-reproduce/e/reproduction-in-animals 2026-04-10T12:00:44.946307725Z Reproduction in animals Let's solve some problems to better understand reproduction in animals. Aakash Bagga exercise https://www.khanacademy.org/science/bridge-course-class-10th-science/x37589313f9a4c197:week-3/x37589313f9a4c197:how-do-organisms-reproduce/e/reproduction-in-humans 2026-04-08T04:40:58.254797178Z Reproduction in humans Let's solve some problems to better understand the male/female reproductive systems in humans. Aakash Bagga exercise https://www.khanacademy.org/science/revision-term-2-tg-biology-class-8/x04828215b460a495:week-3/x04828215b460a495:reproduction-in-animals/e/viviparous-and-egg-bearing-animals 2026-04-10T12:00:44.946307725Z Viviparous and egg-bearing animals Let's solve some questions on Viviparous and egg-bearing animals Vibhor Pandey exercise https://www.khanacademy.org/science/bmc-grade-7-science/x2dc8db125f483583:properties-of-natural-resources/x2dc8db125f483583:human-impacts-on-sustainability/v/earths-changing-climate0in 2025-07-09T07:55:11.377063168Z Earth's changing climate Let's learn about Earth's changing climate Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Earth's changing climate Let's learn about Earth's changing climate https://cdn.kastatic.org/ka-youtube-converted/3hDAQxKU8UQ.mp4/3hDAQxKU8UQ.mp4 331 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/ap-college-environmental-science/x0b0e430a38ebd23f:aquatic-and-terrestrial-pollution/x0b0e430a38ebd23f:waste-disposal-reduction-and-treatment/v/solid-waste-disposal 2024-06-21T23:15:14.703721694Z Solid waste disposal Solid waste is most often disposed of in open dumps and sanitary landfills. A sanitary municipal landfill consists of a bottom liner (plastic or clay), a storm water collection system, a leachate collection system, a cap, and a methane collection system. However, landfills can contaminate groundwater, cause leachate pollution, and release harmful gases. Solid waste can also be disposed of through incineration, where waste is burned at high temperatures. Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/0b70a8f3-f4f6-4b41-9992-519db064a1c2_1280_720_base.png Solid waste disposal Solid waste is most often disposed of in open dumps and sanitary landfills. A sanitary municipal landfill consists of a bottom liner (plastic or clay), a storm water collection system, a leachate collection system, a cap, and a methane collection system. However, landfills can contaminate groundwater, cause leachate pollution, and release harmful gases. Solid waste can also be disposed of through incineration, where waste is burned at high temperatures. https://cdn.kastatic.org/ka-youtube-converted/LOzMugtKmN4.mp4/LOzMugtKmN4.mp4 476 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/ap-biology/ecology-ap/disruptions-to-ecosystems/v/how-does-climate-change-affect-biodiversity 2024-05-06T19:22:43.24334365Z How does climate change affect biodiversity? Global warming, caused by increasing greenhouse gas emissions, threatens biodiversity. As temperatures rise, species struggle to adapt, leading to extinctions and ecosystem disruptions. Melting ice contributes to sea level rise, endangering low-lying habitats. Additionally, increased carbon dioxide levels affect plant growth and biodiversity, potentially exacerbating climate change through feedback loops. Urgent action is needed to address these challenges and protect our planet's diverse ecosystems. California Academy of Sciences video https://cdn.kastatic.org/googleusercontent/d-YQkLRjmNiut6yWmhv9zRc2_yI-3t5mZFb38VZKHy44nHhmMvWJEFnNdlePvmCNHqsDHkeXIi23btU4mXtZ3Iw-TQ How does climate change affect biodiversity? Global warming, caused by increasing greenhouse gas emissions, threatens biodiversity. As temperatures rise, species struggle to adapt, leading to extinctions and ecosystem disruptions. Melting ice contributes to sea level rise, endangering low-lying habitats. Additionally, increased carbon dioxide levels affect plant growth and biodiversity, potentially exacerbating climate change through feedback loops. Urgent action is needed to address these challenges and protect our planet's diverse ecosystems. https://cdn.kastatic.org/ka-youtube-converted/XFmovUAWQUQ.mp4/XFmovUAWQUQ.mp4 727 Our Home: Earth, a Unique Life Sustaining Planet https://www.khanacademy.org/science/class-7-science/x0c8b40bd4b242f0b:air/x0c8b40bd4b242f0b:air-pollution/e/air-pollution-middle-school-india 2026-04-07T23:55:07.30621384Z Air Pollution An exercise dealing with the causes and remedies of air pollution. Joel Prakash Stephen exercise https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:pollution/x0f256b8de9c7cf34:water-pollution/e/pollution-and-conservation-of-water 2024-06-16T13:03:12.23291439Z Pollution and conservation of water Let's solve some questions! vibhor exercise https://www.khanacademy.org/science/ms-biology/x0c5bb03129646fd6:organism-growth-and-reproduction/x0c5bb03129646fd6:sexual-and-asexual-reproduction/v/ms-sexual-and-asexual-reproduction 2024-01-04T21:34:20.525650636Z Sexual and asexual reproduction Reproduction is the process by which organisms create new life. There are two main types: asexual and sexual reproduction. Asexual reproduction involves one parent, producing offspring identical to the parent. Sexual reproduction involves two parents, resulting in genetically unique offspring. Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/cb4fb44c-ac9b-43b8-914a-67697d4e9dc8_1280_720_base.png Sexual and asexual reproduction Reproduction is the process by which organisms create new life. There are two main types: asexual and sexual reproduction. Asexual reproduction involves one parent, producing offspring identical to the parent. Sexual reproduction involves two parents, resulting in genetically unique offspring. https://cdn.kastatic.org/ka-youtube-converted/IZ6EvH240iA.mp4/IZ6EvH240iA.mp4 280 Our Home: Earth, a Unique Life Sustaining Planet