Rough endoplasmic reticulum contains ribosomes, while smooth endoplasmic reticulum does not contain ribosomes. The ribosomes are what give rough endoplasmic reticulum its characteristic "roughness."
Spread of disease is density dependent because it is more severe the greater the population density as the disease would spread more easily. If there is low population density it would spread slower.
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:
Invasive species are among the leading threats to native wildlife. Approximately 42 percent of threatened or endangered species are at risk due to invasive species.