1. Endoderm gives rise to (a) the entire digestive tube, (b) the skin, (c) the neural tube, (d) the kidney, (e) none of these. 2. When it is 1.5 months old, an average embryo is the size of (a) a...

1. Endoderm gives rise to (a) the entire digestive tube, (b) the skin, (c) the neural tube, (d) the kidney, (e) none of these.

2. When it is 1.5 months old, an average embryo is the size of (a) a black bean, (b) an adult fist, (c) its mother’s nose, (d) the head of a common pin.

3. Gastrulation is the (a) formation of three germ layers by the epiblast at the primitive streak, (b) formation of the placenta, (c) same as cleavage, (d) folding of the gut into a tube during week 4.