A sarcomere is the basic contractile unit of muscle fiber. Each sarcomere is composed of two main protein filaments—actin and myosin—which are the active structures responsible for muscular contraction. The most popular model that describes muscular contraction is called the sliding filament theory.
Nucleotide would be the answer
The population of jellyfish would increase and the population of killer whales would decrease
They can keep organ tissue alive for transplantation.
