Show the following as a food chain: omnivore, autotroph, herbivore

omnivore⇒herbivore⇒autotroph

this is because an autotroph makes its own food (photosynthesis) so it doesn't have the need to eat other organisms. Herbivores eat only plans (remember this with the word herb is a type of plant) and an omnivore will eat either meat or plants so it can eat either of the things below it.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.