The enzyme that synthesizes a DNA copy from an RNA template in retroviruses is: MCQ with Answer and Explanation

Explanation:
Minamata disease is a neurological syndrome caused by severe mercury poisoning, first discovered in Minamata, Japan, due to industrial wastewater containing methylmercury that bioaccumulated in fish. Lead causes plumbism, cadmium causes Itai-itai disease, arsenic causes arsenicosis. Mercury affects the central nervous system, causing numbness, muscle weakness, and vision problems.

Explanation:
In C4 plants, the leaves exhibit Kranz anatomy, where the vascular bundles are surrounded by a distinct layer of bundle sheath cells. These bundle sheath cells are large and contain numerous, large chloroplasts that lack grana (agranal). Because they lack grana, they cannot perform the light-dependent reactions (which require PSII, located in the grana) but are highly efficient at performing the Calvin cycle (light-independent reactions) in a high CO2 environment, minimizing photorespiration.

Explanation:
In plant tissue culture, when an explant (a piece of plant tissue) is placed on a nutrient medium containing specific plant hormones (like auxins and cytokinins), the cells dedifferentiate and undergo rapid, unorganized division to form a mass of cells called a callus. This callus is undifferentiated. Under appropriate hormonal conditions, this callus can then be induced to redifferentiate and form organized structures like shoots and roots (organogenesis) or somatic embryos.