With the use of effective vaccines, polio has

become a very rare disease and far fewer
people get polio than once did. This is an
example of ____ selection



a. directional
b. stabilizing
c. disruptive
d. mutational
e. infrequent


A

Biology & Microbiology

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A white blood cell (WBC) encounters bacteria in a scrape on the knee of a child who has fallen off of his bicycle. The WBC's job is to take the bacteria inside of itself and destroy the bacteria. If the bacteria cannot be moved across the WBC membrane, how will the WBC most likely take it in?

a. exocytosis b. pinocytosis c. facilitated diffusion d. phagocytosis

Biology & Microbiology

The last common ancestor shared by humans and chimpanzees lived about

A) 6,000-8,000 years ago. B) 5-7 million years ago. C) 25-40 million years ago. D) 1.5-2.5 billion years ago.

Biology & Microbiology

ATP is produced in the mitochondria by a series of biochemical reactions. In what order do these reactions occur?

A) the electron transport chain; glycolysis; the citric acid cycle B) the citric acid cycle; glycolysis; the electron transport chain C) the citric acid cycle; the electron transport chain; glycolysis D) glycolysis; the electron transport chain; the citric acid cycle E) glycolysis; the citric acid cycle; the electron transport chain

Biology & Microbiology

Mannose sugar occurs on the surface of some bacteria and fungi and can trigger the

A. release of cytotoxins by NK cells. B. release of histamines by basophils. C. classical pathway of complement activation. D. lectin pathway of complement activation. E. release of NETs by neutrophils.

Biology & Microbiology