Which short description best describes the body plan of modern sponges? a gel-like consistency with cells interspersed, making up a semi-solid structure an aggregation of cells built around a water canal system a complete gut with an anterior mouth and posterior anus a mouth connected to a blind sac in which digestion occurs a complete gut with one opening serving as both mouth and anus

The answer is an aggrregation of cells built around a water canal system

Explanation:

Because sponges are the most simple animals that consist of a hollow tube with pores in its wall, without tissues or organs. They only have three types of cells.

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.