The Percentage of Essential Genes in a Genome, as Measured

Multiple Choice

The percentage of essential genes in a genome, as measured in the laboratory, is probably an underestimate because

A) many genes are only essential in poor conditions, not simulated in the laboratory.
B) the functions of many genes are, as yet, poorly understood.
C) some genes are expressed at such low levels that they are not easily detected.
D) All of the answers are correct
E) None of the answers are correct