The opening to the tracheal system (respiratory system) in insects is the
A. spiracle.
B. trachea.
C. alveolus.
D. bronchus.
E. stomata.
A. spiracle.
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A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication?
A. a signaling cell B. a signaling molecule C. a receptor molecule D. a responding cell E. None of these choices are correct.
In which of the following ways does cardiac muscle differ from skeletal muscle?
A. Cardiac muscle is striated and skeletal muscle is not. B. Cardiac muscle surrounds hollow tubes; skeletal muscle attaches to skin. C. Cardiac muscle cells are electrically connected; skeletal muscle cells are not. D. Cardiac muscle is under voluntary control; skeletal muscle is under involuntary control. E. A group of cardiac muscle cells forms an organ; a group of skeletal muscle cells forms a tissue.
The rate which velocity changes with time
What will be an ideal response?
What is not a trace mineral
What will be an ideal response?