The skeletons of rays and skates are made of
A) protein slime.
B) bone.
C) muscle.
D) cartilage.
E) chitin.
D
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Sperm are formed from the direct maturation
of a. sperm mother cells. b. spermatids. c. spermatogonial cells. d. primary spermatocytes. e. secondary spermatocytes
Astrocytes
a. are a type of neuroglial cell found in the brain. b. make nerve growth factor. c. play a role in immune defenses. d. make lactate to fuel active neurons. e. include all of these descriptions.
Pasteur
A. employing a swan-neck flask. B. being the first researcher to work under sterile conditions. C. demonstrating the synthesis of organic molecules. D. showing that maggots arise from eggs laid by flies.
The causative agent of Lyme disease is
A) Borrelia hermsii B) Ixodes scapularis C) Leptospira interrogans D) Ixodes pacificus E) Borrelia burgdorferi