The amount of air that can be forcefully exhaled after a normal tidal expiration is the: MCQ with Answer and Explanation

Explanation:
The skin and mucous membranes form the first line of defense (innate immunity), acting as physical barriers that prevent pathogens from entering the body. White blood cells (leukocytes), including phagocytes and lymphocytes, are the cellular components of the immune system that identify, attack, and destroy pathogens. Antibiotics are drugs designed to kill or inhibit the growth of bacteria; they are completely ineffective against viruses, which lack the cellular machinery targeted by antibiotics. Thus, statements 1 and 2 are correct.

Explanation:
Peroxisomes are single-membrane organelles involved in oxidative reactions, not plastids. Plastids (chloroplasts, chromoplasts, leucoplasts) are double-membrane organelles found in plants and algae, involved in photosynthesis, storage, and pigmentation. Chloroplasts contain chlorophyll, chromoplasts carotenoids, leucoplasts are colorless storage plastids.

Explanation:
Transduction is the transfer of bacterial DNA from one bacterium to another by a bacteriophage. Generalized transduction occurs when phage accidentally packages host DNA; specialized transduction involves specific genes near the prophage integration site. Conjugation needs direct contact, transformation free DNA.