Which of the labeled steps in the diagram represent formation of the primitive heart tube?
a) A
b) B
c) C
d) D
e) E
c
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Lymphocytes that are able to bind and respond to antigen are said to be _______________
Fill in the blank with correct word.
One advantage of signaling pathways involving the generation of second messengers has compared to a signaling pathway that utilizes the influx of ions is
a. the former are much faster in terms of generating cellular responses to first messengers. b. the former are slower in terms of generating cellular responses, allowing cells to be more circumspect in their response to chemical signals. c. the former require less first messenger to elicit a response, since they allow for signal amplification. d. the former require more first messenger to elicit a response, allowing for more rapid termination of the signaling event. e. none of these.
abnormally large or hypertrophied glands tend to produce low hormone levels
a. true b. false
The clear gel that usually surrounds cells is called interstitial fluid
Indicate whether the statement is true or false