A sea urchin sperm penetrates the jelly coat of an egg and adheres to receptor proteins on the egg's surface as a result of __________.

Should parents undergoing in vitro fertilization have the right to choose which embryos to implant based on genetic criteria, such as the presence or absence of disease-causing genes? Should they be able to choose based on the sex of the embryo? How could you distinguish acceptable from unacceptable criteria? Do you think such options should be legislated?

The development of a zygote into a blastula is called __________.

Which stage of development is common in amphibians but not seen in mammals?

Which of the following describes the correct sequence of stages during embryogenesis?

How does a zygote differ from an ovum?

After a sperm penetrates an egg, a fertilization envelope forms. This envelope __________.

The period of repeated cell divisions without significant cell growth results in formation of the blastula and is called __________.

During cleavage the single large zygote is converted into a __________.