Question

researchers used a puppet, line drawings and simple vocabulary to find that children as young as 3 are beginning to ______ that nuanced concept. source: washington times grasp preen infuse depress

Explanation:

To solve this, we analyze the context: the sentence is about children understanding a nuanced concept. "Grasp" means to understand or comprehend, which fits. "Preen" means to groom or show off, "infuse" means to introduce or fill with, and "depress" means to sadden or lower—none fit the context of understanding a concept.

Answer:

A. grasp