Which enzyme hydrolyzes starch into maltose in the human digestive system? 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:
The cortical reaction is a mechanism to prevent polyspermy, ensuring that only one sperm fertilizes the egg. It is triggered immediately after the plasma membrane of the sperm fuses with the plasma membrane of the oocyte. This fusion causes a sudden release of calcium ions inside the oocyte, which triggers the cortical granules (located just beneath the oocyte membrane) to release their contents into the perivitelline space. These enzymes modify the zona pellucida (zona reaction), making it impermeable to other sperm.

Explanation:
In the apoplast pathway, water moves through cell walls and intercellular spaces without crossing membranes. However, at the endodermis, the Casparian strip (suberin deposition) blocks apoplastic movement, forcing water to enter the symplast (via plasma membrane). Thus, apoplastic movement stops at the endodermis. This ensures selective uptake of minerals.