I believe the correct answer from the choices listed above is the first option. <span>The biodiversity and distribution of penguin species in the Antarctic Peninsula are changing as sea ice disappears. This is caused by the climate change which causes glaciers to melt down rising the sea levels. Hope this answers the question. Have a nice day.</span>
Answer:
1. Signaling molecule
2. Signaling receptors
Explanation:
Hormones, growth factors, neurotransmitters, etc. serve the function of signaling molecules for cells. These molecules are released by one cell and bind to the receptors present on/in the target cells to elicit the desired response. Thereby, the signaling molecules serve in cell-cell communication.
For example, insulin hormone synthesized and released from beta cells of pancreas binds to its cell surface receptors present on the surfaces of liver cells and muscle cells to stimulate the uptake of the glucose from the blood.
Likewise, neurotransmitters released from the presynaptic neuron bind to receptors present on the membrane of postsynaptic neuron and serve to carry the nerve impulse to the postsynaptic neuron.
It’s called a slump
Hope this helps :)