Before the Completion of the Human Genome Project,it Was Generally $\times$

Multiple Choice

Before the completion of the human genome project,it was generally estimated that human DNA would contain up to 100,000 genes.We now know humans contain only around 25,000 individual genes within our genomes.This "gene count" is so surprising because:

A) simple roundworms have over 10,000 genes,so humans should have many more.
B) experimental analysis of mRNA diversity generated estimates of ~100,000 genes.
C) humans have a large genome size (3.3 $\times$ 10⁹ base pairs) .
D) the diverse types of tissue in humans require many thousands of genes.
E) All of the answer options are correct.