Explanation:
Natural passive immunity occurs when pre-formed antibodies are transferred naturally from one individual to another. During pregnancy, maternal antibodies (primarily IgG) cross the placenta to the fetus, providing temporary protection against diseases the mother is immune to. Colostrum (mother's milk) also provides IgA antibodies to the newborn.
Explanation:
CFCs, used in refrigerants and aerosol propellants, release chlorine atoms when exposed to UV radiation in the stratosphere. A single chlorine atom can destroy thousands of ozone (O₃) molecules. This led to the formation of the 'ozone hole' over Antarctica. The Montreal Protocol (1987) successfully phased out CFCs, allowing the ozone layer to slowly recover.
Explanation:
Lymphatic filariasis, caused by Wuchereria bancrofti and transmitted by Culex mosquito, leads to chronic swelling of limbs (elephantiasis) due to blockage of lymphatic vessels. Amoebiasis is Entamoeba, sleeping sickness Trypanosoma, kala-azar Leishmania.
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