Identify the correct statement about the human reproductive system: MCQ with Answer and Explanation

Explanation:
Cutin, along with waxes, forms the cuticle on the epidermis of leaves and stems, reducing water loss and providing protection. Lignin strengthens cell walls, cellulose is the wall polysaccharide, suberin is in cork cells and root endodermis.

Explanation:
The skin and mucous membranes act as primary physical barriers in innate immunity, preventing pathogen entry. Phagocytosis by macrophages and neutrophils is a non-specific (innate) cellular defense mechanism, not a specific immune response. Memory B and T cells are produced during the primary specific immune response and provide rapid, long-lasting immunity upon re-exposure. Thus, statements 1 and 3 are correct.

Explanation:
The Miller-Urey experiment (1953) simulated the conditions of the primitive Earth's atmosphere (methane, ammonia, hydrogen, and water vapor) in a closed system and applied electrical sparks to simulate lightning. After a week, they found that several organic compounds, including amino acids (the building blocks of proteins), had been synthesized, supporting the theory of chemical evolution.