Answer:
A. whether the glycoproteins or capsid proteins on its surface recognize those of the host cells.
Explanation:
Virus has different surface proteins that are recognized by the receptors present on its host cell. The range of a virus is determined by the recognition of these proteins by the host cell.
The interaction between the receptor on the host cell and surface proteins on the viral capsid is important for viral genome entry in the host cell and to determine the range of the host cells.
If the surface protein of the virus is not able to bind to the receptor on any cell then the virus can not infect the cell. For example, the HIV virus infects only those cell which have CD4 receptors. So the right answer is A.
Answer:
The correct option is D) The age-structure diagram would be column-shaped with all age classes approximately equal.
Explanation:
A zero population growth refers to a condition when the birth rate equals to the death rate. Social workers tends to find methods to attain zero population growth as such conditions provide economic stability. As the birth rate and the death rate will be equal hence the age structure diagram of such a population can be seen to be column shaped as they all will be equal.
A male drake will result with XY chromosome and a female drake would have XX chromosomes
Answer:
A. It is a type of galaxy that is an intermediate between a spiral galaxy and elliptical galaxy
Explanation:
If a zebra mussel is discovered in a lake in Pennsylvania, then the ecologist would be worried because it is an invasive species. The zebra mussel is native to Ukraine and Russia, but if it has been found in Pennsylvania, than it means that it has been introduced in this area. As an invasive species, the zebra mussel can be very dangerous for the native species in the lake. The invasive species usually are more competitive for food sources than the native species, manage to reproduce quicker, bring in diseases, and the native species tend to not have defense mechanisms for them. This leads to rapid decline or even extinction in the native species, while the invasive spreads out quickly and takes over, resulting in dramatic change in the whole ecosystem.
