Sexual differentiation of the embryo is normally determined by
A. the number of chromosomes, with males having 22 pairs and females having an extra pair of XX chromosomes.
B. the presence of two X chromosomes, which causes the primordial testes to degrade.
C. hormones produced by the placenta.
D. the presence of one Y chromosome, which causes the primordial ovaries to degrade.
E. the presence of the Y chromosome, which directs the undifferentiated gonads to develop into testes (when there is one X chromosome present as well).
Answer: E
You might also like to view...
One of the main differences between a somatic reflex and autonomic reflex is the type of effectors that are activated. The effectors in somatic reflexes are _____, while the effectors in autonomic reflexes are _____
a) skeletal muscles; smooth muscle, cardiac muscle, and glands b) striated muscles; smooth muscle and glands c) skeletal muscles and glands; smooth muscle and cardiac muscle d) glands; skeletal muscles, smooth muscle, and cardiac muscle e) skeletal muscles; smooth muscle only
Ingestion of food results in water
A. output, as food absorbs water and we lose more water through feces than we gain through eating. B. intake, as food contains some water.
The hypothalamus synthesizes the hormones released by the anterior pituitary
Indicate whether the statement is true or false
The peritoneal cavity contains which of the following?
(A) liver (B) pancreas (C) large intestine (D) kidney (E) peritoneal fluid