Answer:
Option A, Key stone
Explanation:
A keystone species plays a major role in an ecosystem as it is the species whose presence effects all other species in the ecosystem .In general a keystone species is always a dominant predator that feed on prey population. If it is removed, the prey population will explode and the population diversity will reduce. For example - bison, prairie dog etc.
Hence, option A is correct
When you swallow food, it doesn't just drop down into your stomach. Muscles contract in a wave-like motion to move the food along through the esophagus. This muscle movement is called, peristalsis, or peristaltic waves. These peristaltic waves contract behind the food bolus pushing it along the digestive tract.
Answer:
The models are missing in the question. The models along with the question is provided in the attachment below.
The answer is : Model A represents the Plasma membrane.
Explanation:
According to the question, model A represents the plasma membrane. The reasons are :
(a). In the model A, the bilayers consists of two leaflets of the amphipathic lipid molecules. Here the polar head groups is in contact with the intra cellular or the extra cellular non aqueous phase, where the non polar tails are facing each other constituting the hydrophobic interior of the membrane.
(b). Lipid are not rigid as well as static structure. In the lipid bilayer, the lipid molecule are able to rotate around their axis freely and diffuse laterally with each leaflet.
(c). The plasma membrane acts as the selective plasma membrane.
Sometimes genes change their form in a process without a reason and it's called spontaneous mutation. Spontaneous mutations<span> occur with non-zero probability. And they occur even in an uncontaminated cell. They are characterized by the specific changes.</span>
<span>The answer to your question is that all of the energy is ultimately radiated into empty outer space as heat. The second law of thermodynamics mandates that all processes that involve the transfer of energy MUST radiate a portion of this energy into space as waste heat. This is why when you run down the street you get hot and sweaty, and this is why automobiles MUST have a functioning radiator and nuclear power stations MUST have evaporation cooling towers or else be located near a large body of water to exchange excess waste heat into, etc., etc. It is also true that the transfer of energy at each step up the food chain is very inefficient. They say it takes around 50 lbs of corn to produce one pound of beef, and it probably takes 20-30 pounds of beef to produce one pound of human tissue. The rest of the energy just goes into your living room as radiated body heat. I hope this helps.</span>
