Which of the following explains why water can support life below water? - Water is denser when frozen, protecting underwater organisms.
- Water cools and heats very quickly to protect aquatic ecosystems.
- Water can dissolve most substances in their solid, liquid, and gas form.
- Water cannot move against gravity; this keeps its molecules together.

b. read the phase at the intersection of any given temperature and pressure.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.

it is called the mitotic spindle