An amoeba is a single-celled organism that feeds on algae, plant cells, and bacteria. When an amoeba feeds, it first makes contact with the food particle. Next, the amoeba starts to surround the particle. Once the particle is completely engulfed, it is surrounded by a layer of the amoeba's membrane, forming a vesicle. The pH in the vesicle is then lowered and the contents are degraded. What type of transport is involved in this process?

A. passive transport
B. diffusion
C. exocytosis
D. endocytosis

this would be a math

the areas around the equator

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.