Retrotransposons are class of transposons that contain long terminal repeats and code for an enzyme that synthesize DNA using an RNA template. It is found in all eukaryotes but absent in prokaryotes. About 42% of human genome is made up of retrotransposons. They are particularly abundant in plants, in maize 49-70% genome is made up of retrotransposons.
Answer:A. The release of calcium ions causes myosin and actin to attach to each other.
The contraction of skeletal muscles takes place by induction of a nerve impulse, which produces a movement and the interaction of the filaments containing proteins named as actin and myosin. This interaction of filaments is regulated by proteins called tropomyosin and troponin present on the actin filaments. The motor nerve causes the depolarization of the muscle membrane sarcolemma. This triggers the sarcoplasmic reticulum to release calcium ions. This calcium binds to troponin and thus allows the tropomyosine strand on the actin filament to displace so that the part of the actin where myosine head needs to be attached remain uncovered. Binding of the actin myosine filament results in contraction.
Hence, the release of calcium ions causes myosin and actin to attach to each other causes muscle contraction.
Ethonal is produced during b. Alcohol fermentation that converst sugars into ethanol.
The answer is D. The surface area of rocks decreases because of acid rain
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C. pass those traits on to future generations