Consider statements about plant tissues: 1. Parenchyma cells have thin cell walls. 2. Collenchyma provides mechanical support. 3. Sclerenchyma cells are living at maturity. Which are correct? MCQ with Answer and Explanation

Explanation:
Jonas Salk developed the inactivated polio vaccine (IPV) in 1955, which was the first effective vaccine. Albert Sabin later developed the oral polio vaccine (OPV). Pasteur rabies, Jenner smallpox.

Explanation:
The inner surface of the small intestine is lined with finger-like projections called villi, which increase the surface area for absorption. The epithelial cells (enterocytes) covering these villi have their own microscopic, finger-like projections on their apical surface, called microvilli. Collectively, these microvilli form a 'brush border'. This further massively increases the surface area, maximizing the efficiency of nutrient absorption. Cilia are motile, and stereocilia are found in the inner ear and epididymis.

Explanation:
Parthenocarpy is the development of fruit without fertilization, leading to seedless fruits like commercial banana, navel orange, and some grapes. It can be natural or induced by hormones. True fruits develop from ovary after fertilization.