In which structure do monotreme embryos develop? a. a placenta
b. an egg
c. a yolk
d. a pouch

The correct answer is B. Monotreme embryos develop in an egg.

Explanation:

Monotremes are the mammals that, like the platypus, develop in eggs. Thus, this class of mammals is the only one with this condition, which is shared with reptiles and birds.

Monotremes are considered to be animals with a prehistoric development, so this characteristic of being developed in eggs is a condition that originates in the historical period in which these animals emerged.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

meiosis is the correct answer