It is essential in modern society that ______.(具备应对突发情况的能力).

A．The genes of Alzheimer’s disease have been decoded after the decoding of human genome.
B．Brain diseases usually are the outcome of interaction of complicated groups of genes.
C．The scientists’ findings on genes have quickly lead to understanding of mental diseases.
D．the complexity had stopped the researchers from come up with treatment to mental diseases.

A．work
B．livelihood
C．jobs
D．family