The human disease characterized by the formation of amyloid plaques in the brain is: MCQ with Answer and Explanation

Explanation:
A population is a group of individuals of the same species living in a specific geographic area and capable of interbreeding. A community comprises all the interacting populations of different species (plants, animals, microbes) living together in a defined area. An ecosystem is a functional unit of nature that encompasses both the biotic (living community) and abiotic (non-living physical environment like soil, water, sunlight) components, interacting as a complex system. All statements are correct.

Explanation:
Elephantiasis, or lymphatic filariasis, is caused by parasitic nematode worms, primarily Wuchereria bancrofti (responsible for about 90% of cases), Wuchereria malayi, and Brugia timori. These worms are transmitted by mosquitoes (like Culex). The adult worms lodge in the lymphatic vessels, causing severe inflammation, blockage, and damage to the lymphatic system. This leads to the accumulation of lymph fluid and massive, disfiguring swelling (edema) of the limbs, genitals, and breasts, resembling an elephant's skin and legs.

Explanation:
Iron (Fe²⁺) is at the center of the heme group in hemoglobin, enabling reversible oxygen binding. Calcium is in bones, magnesium in chlorophyll, zinc in many enzymes. Iron deficiency leads to anemia.