Evolutionary biologists say that there is a good reason for gaps in the fossil record. Can you explain why some animals and plants were never fossilized?

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.

i think its both a and b

answer; cnidarians;