Which of the following is (are) found in many veins that help direct blood flow in one direction only: toward the heart?

A) valves
B) lymph nodes
C) myocardium
D) pericardium


A

Biology & Microbiology

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Which of the following is a step in a PCR?

A. DNA is cooled to a temperature at which the hydrogen bonds holding the strands break. B. The primers anneal to the complementary sequences on the template DNA C. DNA gyrase enzyme relieves the supercoiling ahead of the replication fork. D. The DNase I synthesizes a new strand of DNA that is complementary to the template DNA.

Biology & Microbiology

The pattern of locomotion used by gibbons and siamangs, in which they use their arms to hang below branches and

swing forward, is called ____.

a. bipedal movement b. peristalsis c. gliding d. brachiation e. orthokinesis

Biology & Microbiology

What marine biology laboratory inspired other facilities of the same kind?

a. Marine Biological Laboratory at Woods Hole b. Friday Harbor Laboratories of the University of Washington c. Museum of Comparative Zoology at Harvard University d. Scripps Institute of Oceanography in California

Biology & Microbiology

Meiosis can occur

a. in all sexually reproducing organisms. b. only when an organism is diploid. c. only in multicellular organisms. d. only in haploid organisms. e. only in single-celled organisms.

Biology & Microbiology