Answer:
The snakes keep the mice from overpopulating, which could deplete their resources.
Explanation:
The mice and the moles are not competing against each other as they feed on different food. The problem is that if the mice population is not regulated, their very quick reproduction will cause overpopulation in very short space of time. The more mice there will be , the more food will be needed, so very soon the resources will be depleted, resulting in collapse of the mice population. This is where the snakes come in action, as they eat mice, so they are the ones that control and keep their population stable, thus not allowing the mice to overpopulate the area and destroy themselves.
Answer:
the dissolved oxygen of the water decreases.
the fish need the oxygen for respiration, breathing through their gills.
Explanation:
The salinity decreasing doesn't affect the pickerel, because it's a freshwater fish. no salt needed.
more light penetrating the water just means that more aquatic weed or grasses would grow, giving the pickerel more area to spawn their eggs.
temperature increase in the summer has no affect on the fish, since the spawning happens in late winter.
Answer:
Nervous system: This systems helps the five sense organs (eyes, ears, nose, tongue, skin) which all contain nerves that send messages to the brain about what is happening. The brain produces a response which it sends via other nerves to the muscles.
Digestive system: This system helps to break down food into simpler substances so it can be used and absorbed into the body. It takes place in the alimentary canal (food tube), mainly in the stomach and small intestine. The digested food is absorbed into the blood.
Respiratory System: This system helps take in oxygen and removing waste carbon dioxide. Air enters the lungs by movement of the rib muscles and diaphragm. The oxygen is absorbed into the blood.
Reproductive system: This helps produce offspring. Eggs are produces by ovaries in a female and the sperm is produced in the testes of a male. They then try and fertilise the eggs.
Note:
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