D. This is to “proofread” the DNA
<span>Rh-positive fetus and an Rh-negative mother condition occur.</span>
Answer:
C
Explanation:
Many kinds of air pollution can't be seen, which means A is incorrect. Any kind of pollution can be harmful to you, which means B is incorrect too. Air pollution is very harmful but in most cases can't be directly seen, so C is correct. Pollution can be found everywhere, so D is incorrect also.
