Answer
HBA HBs
Explanation:
In some parts of Africa, up to 20% of the population are carriers of the sickle cell gene. This suggests that the trait must have a survival value. The carriers of the trait have a much lower susceptibility to malaria than normal individuals. This is because the malaria parasite survives very poorly in sickled red blood cells.
Considering the following statements;
A. The trait is the same for all organisms
B. The trait is resistant to mutations
C. Most forms of the trait have the same impact on survival
D. The trait is passed on genetically to the next generation
The correct answer is D.
Genetic variation is essential for natural selection since natural selection can only increase or decrease frequency of alleles that already exist in the population. Genetic variation is caused by mutation and random mating organisms.
Answer:
Cancer is basically a disease of uncontrolled cell division. Its development and progression are usually linked to a series of changes in the activity of cell cycle regulators. For example, inhibitors of the cell cycle keep cells from dividing when conditions aren’t right, so too little activity of these inhibitors can promote cancer. Similarly, positive regulators of cell division can lead to cancer if they are too active. In most cases, these changes in activity are due to mutations in the genes that encode cell cycle regulator proteins.
Explanation:
The lining attached to the lungs is called the visceral pleurae.
