Answer: Sickle cell anemia is a molecular and genetic disease.
Sickle cell anemia is not infectious
Diseases caused by microorganisms are infectious.
Explanation: Sickle cell disease is a molecular disease,it involves molecular change in the structure of the molecular base present in the molecule DNA which caused the amino acids and the beta side of the hemoglobin to change accordingly.
It is genetic as it can be transferred from one generation to the next, children can inherit it from their parents.
A person can not be infected with Sickle cell anemia,it is not infectious unlike diseases caused by microorganisms that can infect others who come in contact with the disease either through blood or other routes.
1) Colonial organisms require large areas with resources to sustain the entire colony, just as colonial people do. They are unable to grow in places that are sufficient to sustain a small number of organisms and if their population becomes to large, the colony collapses on itself. This is all visible in people as well.
2) Colonial organisms have greater safety due to their large numbers; however, unlike individual organisms, they are unable to sustain themselves with a smaller number of resources and migrating from one area to another is also more difficult for them.
3) A multicellular organism is more mobile and able to perform more functions in a better manner; however, this also leads to greater energy requirements than that of a single celled organism.<span />
Homozygous for allele A and heterozygous for allele B. So the answer would surly be D.