AP BIOLOGY

Detailed explanation-1: -Carbon is the universal building block for life as we know it. Its ability to form complex, stable molecules with itself and other elements, particularly hydrogen, oxygen, and nitrogen is unique.

Detailed explanation-2: -Turns out our shiny satellite’s surface has hydroxyl molecules-OH, made up of hydrogen and oxygen, the building blocks for the liquid vital for human life. (Hydroxyl can be found around the solar system as well.)

Detailed explanation-3: -Living organisms are primarily composed of water and cannot function without it, although the resting stages for some organisms can survive with very little. In aquatic habitats, water is a source of oxygen (i.e., dissolved oxygen) and food (e.g., suspended particles of organic matter).

Detailed explanation-4: -The Earth is made up of combinations of carbon, oxygen, magnesium and silicon, but the precise ratios of these can have profound impacts on whether a planet ends up with plate tectonics, a cool surface and–ultimately–life.