Answer:
Explanation:
In a lake, oxygenic phototrophs produce new organic material as well as O₂. If primary production rates are very high, the resultant excessive organic matter production can lead to bottom-water O₂ depletion from respiration and the development of anoxic conditions. This in turn stimulates anaerobic metabolisms, including anaerobic respirations and fermentations.
Organic matter that is not consumed in surface layers sinks to the depths and is decomposed by anaerobes.
A unicellular or single celled organism is the term for organisms composed of only one cell.
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Answer: CHANNEL PROTEINS provide openings in the plasma membrane for substances to flow through without changing structure, and CARRIER PROTEINS allow passage of substances through the plasma membrane after undergoing a subtle change in shape.
Explanation: They are described thus:
A channel protein is a protein that allows the transport of specific substances across a cell membrane.
Carrier proteins are proteins that carry substances from one side of a biological membrane to the other. Many carrier proteins are found in a cell’s membrane, though they may also be found in the membranes of internal organelles such as the mitochondria, chloroplasts, nucleolus, and others.
Many act as decomposers, breaking down the dead bodies of plants and animals and recycling the nutrients they hold. ... The fungal decay makes these nutrients and carbon dioxide available to green plants for photosynthesis, and it completes an important cycle of raw materials in the ecosystem.
