The Accompanying Figure Shows How Levels of a MicroRNA Called

The accompanying figure shows how levels of a microRNA called miR-320b change with age in the prefrontal cortex of the brains of humans,chimps,and macaques (African monkeys) .This may be important for understanding the genetic features that make us human,because microRNAs ________.

A) are found only in primates
B) are translated into short polypeptides
C) influence gene expression by binding to messenger RNAs
D) are transcribed from "selfish DNA" sequences such as Alu elements
E) are known to increase neuronal connectivity and therefore intelligence