What advantage do organisms in a food web have over those in a food chain?
a. organisms in a food web have alternative foods to eat if one of their food sources diminishes or disappears.
b. organisms in a food web are on the highest trophic level of feeding stages.
c. organisms in a food web have equivalent survival rates to those in a food chain because they are herbivores.
d. organisms in a food web have one primary food source, which ensures their health.

A.Organisms in a food web have alternative foods to eat if one of their food sources diminishes or disappears.

Food chain refers to a process cycle from producer to consumer to decomposer.
Example:
Plants – herbivores – omnivores – carnivores Start -> Plants -> herbivore insect -> spiders -> small bird -> Snake -> hawk -> fox -> lion -> when died the body will be eaten by hyena-> when hyena died -> body get decompose and be eaten  by worms and the rest will be plant’s fertilizer.

The process of the food chain will then again takes place over and over again. 

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Answer collision and mountain formation;