The bacterium that converts milk into yogurt is: MCQ with Answer and Explanation

Explanation:
Charles Darwin, in 'On the Origin of Species' (1859), proposed natural selection as the mechanism for evolution, based on variation, inheritance, and differential survival. Mendel discovered genetics, Pasteur disproved spontaneous generation, Lamarck proposed inheritance of acquired characters. Wallace independently arrived at natural selection.

Explanation:
B lymphocytes (B cells) differentiate into plasma cells that produce and secrete antibodies (immunoglobulins) specific to antigens, providing humoral immunity. T cells are involved in cell-mediated immunity. Erythrocytes carry oxygen, platelets clot blood, monocytes differentiate into macrophages that phagocytose pathogens. Lymphocytes are a type of white blood cell.

Explanation:
Root hairs are unicellular extensions of epidermal cells found in the zone of maturation (differentiation) of the root, just behind the zone of elongation. They increase surface area for water and mineral absorption. The root cap protects the tip, the meristematic zone contains dividing cells, and the elongation zone causes root lengthening.