Which characteristic of the male reproductive system is not variable among animal species that reproduce sexually?

The question is incomplete as it does not have the options which are:

A.) Presence of genitalia.

B.) Shape of genitalia.

C.) Presence of a scrotum.

D.) Composition of accessory fluids.

Option-A

Explanation:

The reproductive system which is the system formed by the organ which is involved in the reproduction in an organism. These reproductive organs are known as genitalia. Since reproduction is one of the criteria of the cellular organisms, reproduction is possessed by all the organisms on Earth.

The animals which bear the reproductive structures therefore always show the presence of both internal and external reproduce organs like testes, Vas deferens as internal organs and penis and scrotum as external organs.

Thus, Option-A is correct.

substitution is the answer in this case

answer;

a. sheep consumption efficiency would be reduced.

explanation;

-trophic efficiency is a measure of how much energy occurs at one level divided by the energy at the level immediately below it . trophic efficiency incorporates three types of efficiency:

-the proportion of available energy that is consumed (consumption efficiency).   it is the proportion of the available biomass that is ingested by consumers.

-the proportion of ingested food that is assimilated (assimilation efficiency).

-the proportion of assimilated food that goes into new consumer biomass (production efficiency).

-in this case, the grasshoppers would affect sheep by reducing the proportion of the available biomass that is ingested by the sheep.