A reproductive difference between sea urchins and humans is
A) the sea urchin egg completes meiosis prior to fertilization, but meiosis in humans is completed after fertilization.
B) sea urchin eggs are produced by meiosis, but human eggs are produced by mitosis.
C) sea urchin eggs and sperm are of equal size, but human eggs are much bigger than human sperm.
D) sea urchins, but not humans, have a need to block polyspermy because only in sea urchins can there be more than one source of sperm to fertilize the eggs.
E) sea urchin zygotes get their mitochondria from the sperm but human zygotes get their mitochondria from the egg.

Question

Quizplus · Accepted Answer

Sea urchin eggs complete meiosis prior to fertilization, which means that they have already divided their genetic material into haploid cells. In contrast, human eggs complete meiosis after fertilization, which occurs when the sperm enters the egg. This means that when the sperm fertilizes the human egg, the egg still has a full set of chromosomes, and the fertilized egg will go through the process of meiosis to divide the genetic material.

A Reproductive Difference Between Sea Urchins and Humans Is