What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water?
a. Extraembryonic membranes
b. Yolk
c. Cleavage
d. Gastrulation
What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water?
a. Extraembryonic membranes
b. Yolk
c. Cleavage
d. Gastrulation
If an egg cell were treated with EDTA, a chemical that binds calcium and magnesium ions,
a. The acrosomal reaction would be blocked.
b. The fusion of sperm and egg nuclei would be blocked.
c. The fast block to polyspermy would not occur.
d. The fertilization envelope would not form.
In humans, identical twins are possible because
a. Extraembryonic cells interact with the zygote nucleus.
b. Convergent extension occurs.
c. Early blastomeres can form a complete embryo if isolated.
d. The gray crescent divides the dorsal-ventral axis into new cells.
Each blue circle in the figure below represents a cell in a cell lineage. Draw two modified versions of the cell lineage so that each version produces three cells. Use apoptosis in one of the versions, marking any dead cells with an X.