D, a sonic boom is only produced when a body is traveling faster than sound
Answer:
A food web consists of all the food chains in a single ecosystem.
Explanation:
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Answer:
Single celled organism do not contactile vacuoles
Explanation:
The point of the contractile vacuole is to pump water out of the cell through a process called osmoregulation, the regulation of osmotic pressure.
Answer:
Primary active transport
Explanation:
Primary active transport is the transport in which molecules are moved against their gradient, with direct use of ATP as an energy source. Na/K pump is an example of primary active transport: Na ions are transported out of cell, K ions are moved into the cell. This pumps maintain concentrations of those ions and also creates voltage across the cell membrane, which can be used for the secondary active transport of other molecules (e.g. glucose).
Answer:
C. is unstable, with a short half life
Explanation:
Paracrine hormones are the hormones that act on neighboring cells only. These hormones or chemicals are largely unstable and have a brief life as do not visit the distantly placed target cells. For instance, somatostatin is secreted by D cells of the pancreas. It acts in a paracrine manner and inhibits the discharge of hormones from the neighboring beta and alpha cell.
Likewise, one of the functions of unstable NO gas is to serve as a vasodilator. It is released by epithelium cells and serves to dilate arterioles and relax precapillary sphincters. Then it is degraded.
