Which of the three major lines of defense functions to prevent pathogens from entering the body?
A) phagocytic white blood cells
B) skin and mucous membranes
C) acquired defenses
Answer: B) skin and mucous membranes
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Laboratory animals must be used to determine lethal and infectious doses of viruses.
Answer the following statement true (T) or false (F)
Bifidobacterium bifidum is a major pathogen in breast-fed babies.
Answer the following statement true (T) or false (F)
The important feature of all cells that react to a
specific hormone is the a. type of blood supply they receive. b. proximity of the endocrine gland. c. presence of an appropriate receptor molecule. d. characteristic of their mitochondrial membrane. e. presence of specific genes responsive to the hormone.
Besides sending messages to and from the brain, the spinal cord has another important function: Reflexes. In fact, in very simple animals, that is the main function of the cord. In higher animals, reflexes are important because they provide
A. maintenance of life-sustaining processes such as breathing and heart beat, even while sleeping or unconscious. B. protection from sudden or unexpected environmental harms. C. objective physical evidence of neurological injury. D. stimulation of the brain as a protection against atrophy in situations where voluntary movement is hindered, such as a coma.