Answer:
When calcium concentration increases during depolarization, it shifts the conformation of troponin and tropomyosin, and actin is able to associate with myosin. As calcium is taken up again by the sarcoplasmic reticulum the muscle cell relaxes.
We must first define these three prominent definitions of species. Biological species concept means that organisms resemble each other because of genes being passed from parent to offspring. Phylogenetic species concept means that organisms resemble each other because they evolved from a common ancestor. Lastly, morphological species concept characterizes species on the structure of their body parts rather than genetic or phylogeny.
In this case, (1) biological species concept is not applicable for extinct species, (2) phylogenetic species concept is based on evolutionary history, (3) morphological species concept relies on similarities in structure, (4) Morphological and phylogenetic species concept accommodates asexual reproduction, and lastly (5) all species concepts are used by scientists in classification.
