Excitation-contraction coupling refers to the series of events that begins with the excitation of the sarcolemma in response to stimulation by a neurotransmitter, and results in the release of calcium ions from the sarcoplasmic reticulum.
Hence, option D is the 1st process that starts the excitation-contraction coupling.
Phenotype? I think that's it
<span>Insects are found in almost all ecosystems on Earth, with the rarity being oceans. While some species, such as coconut crabs, sand hoppers, woodlice and pill bugs dwell on land, crustaceans are generally found in water — and usually oceanic — regions. Adapting to their habitat, many insect species evolved wings — two pairs for most and one pair for others. A tracheal system is also present for breathing. Crustaceans, on the other hand, breathe using gill-like mechanisms.</span>
Both are types of potential energy
both involve stored energy
