What accounts for the diversity of cell types and functions in humans relative to simpler animals, despite not having significantly more genes than simpler animals? (select all that apply.)
a. many human genes can encode multiple proteins.
b. complexity arises from differential gene expression.
c. humans gain more genes through horizontal gene transfer.
d. complexity arises from different combinations of proteins.

The correct answer are options a, b and d.

Explanation:

The diversity of the types of cells and the functions in humans in comparison to simple animals can be accounted for various reasons. Some of them are as follows:  

a. The genes in eukaryotes like in humans encode for various multiple proteins.  

b. Differential gene expression results in complexity.  

c. Complexity also originates due to the distinct combination of proteins.  

answer; i believe that the correct answer is(d) nondisjunction during meiosis;