3. Explain the digestion of a bite of mixed feed in a cow and a pig. Do this in a stepwise progression beginning with prehension and ending in defecation.

Answer and Explanation:

The process which our body uses to absorb and breakdown nutrients stored in food are called digestion. The cow has a unique digestive process to break down the food. It has four stomachs. When a cow takes a bite of food, it chews the food very little and then swallow. The reticulum and the rumen are the first two cats' stomach; the unchewed food travels to these stomachs—the food stored in this two stomach until later. Cow rests when this process of eating is completed. Later, cow coughs up unchewed food bits named cuds and chewed it thoroughly before swallowing again. The omasum and abomasum are the third and fourth stomach of a cow. The cuds then go to them, where it is completely processed. Some digested food enter in the bloodstreams, while rest goes towards the nourishment of cow. In the pig, the digestion of food starts in the mouth. Food is masticated into small pieces and mixed with saliva, then swallowed. After swallowing the food, it moves down into the stomach. In the stomach, food mixed with enzymes which help in the breakdown of the food. The food enters in the small intestine, where most of the digested food is absorbed. Then the food enters the large intestine. Large intestine absorbs salts and water from undigested material and get rid of left-over.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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a fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis.[1] the age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years.[2] fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas.[3] other commonly used derivatives include kerosene and propane. fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. methane can be found in hydrocarbon fields either alone, associated with oil, or in the form of methane clathrates.

the theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the earth's crust over millions of years was first introduced by andreas libavius "in his 1597 alchemia [alchymia]" and later by mikhail lomonosov "as early as 1757 and certainly by 1763".[4] the first use of the term "fossil fuel" was by the german chemist caspar neumann, in english translation in 1759.[5]

in 2017 the world's primary energy sources consisted of petroleum (34%), coal (28%), natural gas (23%), amounting to an 85% share for fossil fuels in primary energy consumption in the world.[6] non-fossil sources in 2006 included nuclear (8.5%), hydroelectric (6.3%), and others (geothermal, solar, tidal, wind, wood, waste) amounting to 0.9%.[7] world energy consumption was growing at about 2.3% per year. in 2015 about 18% of worldwide consumption was from renewable sources.[8]