The mitochondria is the powerhouse of the cell. on a serious note, The most prominent roles of mitochondria are to produce the energy currency of the cell through respiration, and to regulate cellular metabolism
<span>When an overwhelming body of observations and measurements supports a scientific hypothesis or group of related hypotheses, it becomes a scientific theory. A scientific theory is defined as an explanation of an facet of the natural world that one can test repeatedly using defined protocols of observation and experimentation.</span>
Answer:

Option B is correct.
Explanation:
There are <u>thousands</u> of proteins and only 20 amino acids.
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Answer:
The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere. Since our planet and its atmosphere form a closed environment, the amount of carbon in this system does not change .
Excess carbon in the atmosphere warms the planet and helps plants on land grow more. Excess carbon in the ocean makes the water more acidic, putting marine life in danger. Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt.