I believe the correct answer is a. mutations.
An intrusion is the action of intruding or intruding. I hope I helped a little!! :-)
They replicate fast - producing more of the useful proteins such as the hormone insulin.
The phase of the moon now is Waxing gibbous. Gibbous means that the other half is visible but is not full. This phase includes the night after first quarter and the night before the full moon.