How can you distinguish between the blastocyst and the gastrula stage

Blastocyst is an early embryonic stage in mammals otherwise it is a blastula which is followed by development of gastrula. Blastocyst is a hollow ball like structure that develops by repeated cell division from zygote . It is superficially covered by a layer of cells collectively termed trophoblast.

Explanation:

sorry, but you do not have posted the diagram.

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.