The correct answer is c. Heterotrophs compete for the same food source.
As it can be seen from the image of the food web, the tree or plants which are autotrophs are consumed by various heterotrophs. Autotrophs provide as a source of food for several heterotrophs but several heterotrophs depend on other heterotrophs such as smaller insects or animals for their food. As shown in the food web, both frog and lizard are consumers of insects so both being heterotrophs are competing for the same source of food which is insect here.
Sickle cell anemia is a genetic disease with severe symptoms, including pain and anemia. The disease is caused by a mutated version of the gene that helps make hemoglobin — a protein that carries oxygen in red blood cells. People with two copies of the sickle cell gene have the disease.
According to the question, mating between two populations of Rhagoletis produce hybrid flies.
This means that the two population is present in the same habitat or locality, hence they are capable of coming in contact with each other and mate. Hence, the answer cannot be Habitat Isolation.
Mating produces hybrid flies. This is possible when the gametes (egg and sperm) of the two different populations are capable of capable of coming close to each other and undergoing fusion (fertilization). Hence, there is no Mechanical Isolation.
The zygote formed by the above fertilization is capable of developing into healthy hybrid flies with normal life span. Hence, Pre-zygotic Isolation is absent.
But the hybrid flies formed are sterile and not fertile, that is, they are incapable of producing viable gametes which can undergo fertilization and produce a new offspring.Therefore, the eggs laid by the hybrid flies hatch less often. Hence, there is existence of Reduced hybrid fertility.
Carbon dioxide is transported in the blood in three ways: (i) dissolved in solution; (ii) buffered with water as carbonic acid; (iii) bound to proteins, particularly haemoglobin. Source: https://academic.oup.com/bjaed/article/5/6/207/331369