The accumulation of which chemical compound in the muscles leads to fatigue during strenuous exercise? MCQ with Answer and Explanation

Explanation:
HIV attacks CD4+ T helper cells, progressively weakening the immune system, leading to AIDS, characterized by opportunistic infections and cancers. Hepatitis is liver inflammation often viral, tuberculosis is bacterial, leukemia is cancer of white blood cells. Antiretroviral therapy (ART) controls HIV replication.

Explanation:
Lateral meristems—vascular cambium and cork cambium—are responsible for secondary growth, increasing the girth (diameter) of dicot stems and roots. Apical meristem at root and shoot tips causes primary growth in length. Intercalary meristem at nodes helps in elongation in grasses. Epidermis is a protective outer layer. Secondary growth is absent in most monocots due to lack of vascular cambium.

Explanation:
If two genes are completely linked, they are located very close together on the same chromosome and do not undergo independent assortment or crossing over. They are inherited together as a single unit. A dihybrid cross (RrYy x RrYy) with complete linkage behaves like a monohybrid cross. The F1 produces only parental gametes (RY and ry). The F2 generation will have a genotypic ratio of 1 RRYY : 2 RrYy : 1 rryy, resulting in a phenotypic ratio of 3:1.