Proteins, carbohydrates, nucleic acids, and lipids
The most common organisms with exoskeletons are arthropods which include insects (bees, ants), arachnids (spiders) and crustaceans (lobsters and crabs).
CONTRACTILE RINGS are a contractile ring of actin micro filaments that eventually results in the division of the cytoplasm.
The contractile ring are usually formed during the early anaphase phase of the cell division cycle. During the cellular cleavage, the contractile rings tighten around the cytoplasm of the cell until it is pinched into two daughter cells.
Answer:
Hyaline cartilage is covered externally by a fibrous membrane known as the perichondrium or, when it's along articulating surfaces, the synovial membrane
Explanation:
