Athletes who take synthetic steroids can become sterile due to lack of sperm production. This is because of negative feedback on which of the following?
A. the epididymis
B. the testes
C. the vas deferens
D. the prostate
E. the hypothalamus
E. the hypothalamus
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The 9 + 2 complex refers to ____
a. flagella b. Golgi complex c. ribosomes d. cilia e. both flagella and cilia
What is a main function of the structure in the accompanying figure labeled "A"?
a. It controls cell shape. b. It separates DNA during cell division.
c. It helps nerve cells lengthen. d. It is found in hair. e. It helps regulate DNA replication.
Which of the following is not a type of connective tissue?
a. skin b. adipose tissue c. blood d. bone e. lymph
Which of the following statements would not be consistent with the theory for the endosymbiotic origin of mitochondria and chloroplasts?
A. Mitochondria and chloroplasts have some enzymes unique to them. B. Genes encoded within mitochondria and chloroplasts indicate a closer relationship to prokaryotes than do most nuclear genes. C. The composition of the inner membrane of chloroplasts and mitochondria is similar to the plasma membrane of prokaryotic cells. D. Mitochondria and chloroplasts have their own DNA enclosed within a nuclear envelope. E. The composition of the outer membrane of chloroplasts and mitochondria is similar to the plasma membrane of eukaryotic cells.