What is meant by signal transduction and what is its effect on the process of egg activation?

The process by which a cell responds to substances outside the cell through signaling molecules found on the surface of and inside the cell. ... Signal transduction is important for cells to grow and work normally. Cells that have abnormal signaling molecules may become cancer cells. Also called cell signaling.

Egg activation, whether initiated by or independent of fertilization, induces a rise in intracellular calcium. This calcium increase often manifests as a signaling wave that traverses the egg and releases it from meiotic arrest and metabolic dormancy.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

the answer is:

carbon dioxide