How many trophic levels are there typically in a community

Trophic levels make up the food chain. All food chains and webs have at least two or three trophic levels. Normally,  the maximum trophic levels are four.  

The levels are:

1:  Plants and algae (producers).

2: Herbivores (primary consumers).

3: Carnivores (secondary consumers).

4: Carnivores that eat other carnivores (tertiary consumers).

However, many consumers also feed at more than one trophic level.

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

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.