1 Enzymes associated with the _____ of the sperm help the sperm penetrate the egg.A) head B) tail C) midpiece 2 Gastrulation is complete when _____.A) the blastocoel develops B) three layers of cells are present C) the egg nucleus fuses with the sperm nucleus D) the ectoderm and endoderm are present 3 The _____ is the outer germ layer.A) ectoderm B) endoderm C) mesoderm 4 Which of the choices is the correct order of embryonic stages?
1. Blastula
2. Zygote
3. Morula
4. GastrulaA) 3, 2, 1, 4 B) 2, 4, 3, 1 C) 2, 3, 1, 4 D) 3, 2, 4, 1 5 The _____ is a cavity in the blastula.A) blastocoel B) coelom C) hemocoel D) archenteron 6 Uterine contractions which expel the fetus are initiated by _____.A) prostaglandins B) oxytocin C) androgens D) All of these 7 The last major organ(s) to develop completely is/are the _____.A) lungs B) liver C) kidneys D) heart 8 The baby is delivered during stage _____ of parturition.A) one B) two C) three D) four 9 In humans, the _____ become(s) the thymus gland and parathyroids.A) notochord B) umbilical cord C) pharyngeal arches D) limb buds 10 The developing eyes, ears and nose can be distinguished as early as the _____ week of gestation.A) second B) fifth C) twelfth D) twentieth 11 The blood vessels of the _____ become the umbilical blood vessels.A) chorion B) allantois C) amnion D) yolk sac 12 The trophoblast produces _____, which maintains the corpus luteum and prevents menstruation.A) estrogen B) inhibin C) follicle stimulating hormone D) human chorionic gonadotropin 13 Fertilization occurs in the _____.A) oviduct B) uterus C) vagina 14 The organization of differentiated cells into specific three-dimensional structures is controlled by _____.A) morphogens B) bicoid genes C) homeotic genes 15 The Hox genes _______.A) are located on a single chromosome in humans and mice B) greatly vary from species to species C) are expressed from anterior to posterior in the same order in humans, mice and Drosophila D) All of these 16 When a receptor protein binds a cell-death signal, _____.A) the master ced protein is inactivated B) apoptosis occurs C) proteases and nucleases that slice up proteins and DNA in the cell are produced D) All of these 17 The ability of one embryonic tissue to influence the development of another tissue is called _____.A) morphogenesis B) gastrulation C) induction D) differentiation 18 The adult vertebrate's nervous system arose from the _____.A) ectoderm B) mesoderm C) endoderm 19 Which of the following adult vertebrate structures developed from the mesoderm?A) Skeleton B) Cardiovascular system C) Dermis of the skin D) All of these 20 In the frog, the developing coelom is completely lined with _____.A) endoderm B) ectoderm C) mesoderm