Crease, could you mark brainliest? :)
<span>D) Vaccines allow for building immunity without harmful exposure because not all viruses are safe to be exposed to.</span>
The answer is A. Sound can travel through matter (solids, liquids, and gases). Sound travels faster in solids, then slower in liquids and slowest in the air. When the person in the next room makes noise, the sound travels through the air in their room, through the solid wall and in the air in your room and into your ear.
Sister chromatids have different alleles although carry same genes on same loci. So if it doesn't happen so, like if there are same alleles on sister chromatids then there is a problem in its formation. i.e., male and female alleles haven't contributed equally ( may be an error during their segregation process ). And obviously it doesn't happen in a real cell so we must understand this point. Because normally whenever it happens there's one half from the male and one half from the female. (i.e. maternal and paternal alleles contribute equally).
I hope you get the answer!!!