Dizygotic twins develop from: a. a single fertilized ovum and ...

[james9437]

Dizygotic twins develop from:
 
  a. a single fertilized ovum and are always of the same sex.
  b. a single fertilized ovum and may be the same sex or different sexes.
  c. two fertilized ova and are the same sex.
  d. two fertilized ova and may be the same sex or different sexes.

Question 2

The placenta allows exchange of oxygen, nutrients, and waste products between the mother and fetus through:
 
  a. contact between maternal blood and fetal capillaries within the chorionic villi.
  b. interaction of maternal and fetal pH levels within the endometrial vessels.
  c. a mixture of maternal and fetal blood within the intervillous spaces.
  d. passive diffusion of maternal carbon dioxide and oxygen into the fetal capillaries.

[bpool94]

Answer to Question 1

D
Dizygotic twins are two different zygotes, each conceived from a single ovum and a single sperm. They may be both male, both female, or one male and one female.

Answer to Question 2

A
Fetal capillaries within the chorionic villi are bathed with oxygen and nutrient-rich maternal blood within the intervillous spaces.

[james9437]

TYSM

[sailorcrescent]

Gracias!