General Science: Biology, Environment & Health

Erythroblastosis fetalis (hemolytic disease of the newborn) is the condition caused by Rh factor incompatibility between mother and fetus. When an Rh-negative mother carries an Rh-positive fetus, her immune system may produce antibodies that attack fetal red blood cells, causing severe anemia. Hemophilia is a bleeding disorder, erythropoiesis is RBC production, and myxedema is a thyroid condition.

MAB stands for Man and Biosphere Programme, launched by UNESCO in 1971. It promotes interdisciplinary approaches to conserve biodiversity and ecosystem services while supporting sustainable development. The programme establishes Biosphere Reserves worldwide.

The Chipko movement was an environmental movement in India where villagers hugged trees to prevent logging. It began in the 1970s in Uttarakhand (then part of Uttar Pradesh) and was specifically focused on forest conservation and protecting local livelihoods dependent on forests.

Overgrazing occurs when plants are exposed to intensive grazing for extended periods, or without sufficient recovery periods. This strips the land of vegetation cover, exposes the topsoil, and directly leads to severe soil erosion.

Deforestation destroys habitats, leading to species extinction when animals lose their homes, food sources, and breeding grounds. While hunting (A) and food scarcity (D) can cause extinction, deforestation is the primary driver of widespread wildlife extinction globally due to massive habitat loss.

Silviculture is the branch of forestry concerned with the cultivation, establishment, growth, health, and quality of forests to meet diverse needs and values. Sericulture refers to silk farming, while apiculture is beekeeping.

The Wildlife Protection Act was enacted by the Indian Parliament in 1972 to provide legal protection to wildlife and plants. It was one of India's first comprehensive environmental laws and established the framework for wildlife conservation in the country.

Burning fossil fuels releases sulfur dioxide (SO2), a major air pollutant that contributes to acid rain and respiratory problems. While nitrogen oxides are also produced, SO2 has historically been the primary pollutant associated with fossil fuel combustion, especially from coal power plants.

Hydroelectric power plants generate electricity through water flow without burning fuels, so they don't produce air pollution or greenhouse gases during operation. Pollen grains (A), industries (C), and automobiles (D) all contribute to air pollution - pollen as natural particulate matter, industries through emissions, and automobiles through exhaust.

Continuous sewage flow introduces organic matter and nutrients that stimulate excessive bacterial growth. These bacteria consume oxygen for decomposition, leading to oxygen depletion. Eutrophication and algal blooms are earlier stages; oxygen depletion is the direct consequence that harms aquatic life.

The biosphere encompasses all living organisms and their environments across Earth's three physical spheres - lithosphere (land), hydrosphere (water), and atmosphere (air). Life exists in all three spheres - from deep underground and ocean floors to high in the atmosphere.

Cod liver oil is naturally rich in vitamin A (retinol) and vitamin D. It has been used historically to prevent vitamin deficiencies. The oil is extracted from cod livers and is one of the few natural sources that provides significant amounts of both fat-soluble vitamins.

Iodine deficiency causes goitre (enlarged thyroid gland). Iron deficiency causes anaemia, not rickets. Vitamin A deficiency causes night blindness, not scurvy (that's vitamin C deficiency). Calcium deficiency causes weak bones/osteoporosis, not anaemia.

Vitamin K is essential for synthesizing clotting factors in the liver, making it necessary for blood coagulation. Without vitamin K, blood cannot clot properly. Vitamin A supports vision, vitamin E is an antioxidant, and vitamin C aids collagen production and immunity.

BCG (Bacillus Calmette-Guerin) vaccine specifically protects against tuberculosis, especially severe forms like TB meningitis in children. It is not used for pneumonia, emphysema (a chronic obstructive lung disease), or smallpox (which has a different vaccine).

Respiration is fundamentally about energy liberation - the process where cells use oxygen to break down glucose and release ATP energy. While oxygen intake and CO2 release occur during respiration, they are means to the end of energy production. Options A, B, and C describe only parts of the process.

Frogs use their moist, highly vascularized skin as an accessory respiratory organ for gas exchange (cutaneous respiration), supplementing their lungs. Humans, rabbits, and lizards do not have skin adapted for significant respiratory function - their skin is primarily protective.

CO2 is transported in blood as carbaminohemoglobin (HbCO2) when bound to hemoglobin's amino groups. This accounts for about 20-30% of CO2 transport. NaHCO3 (sodium bicarbonate) is the main transport form (70%), H2CO3 is carbonic acid (transient), and HbCO is carbon monoxide bound to hemoglobin (a toxin, not normal CO2 transport).

People with AB blood type are 'universal recipients' - they have no anti-A or anti-B antibodies in their plasma, so they can receive blood from any group (A, B, AB, or O). However, AB donors can only give to other AB recipients. The question specifically asks where AB donor blood can go.

An antigen is any substance that triggers an immune response and stimulates antibody production. Antigens are not 'opposite' to antibodies (that's backwards), nor are they residues or results of antibodies. Instead, antigens are the foreign molecules or cell-surface markers that the immune system recognizes and responds to by making specific antibodies.

Karl Landsteiner discovered the Rh (Rhesus) factor in 1937 while working with Rhesus monkey blood cells, building on his earlier discovery of ABO blood groups. Harvey studied circulation, Watson and Crick discovered DNA structure, and Darlington worked on chromosomes - none discovered the Rh factor.

Earth is an open system for energy - it continuously receives solar radiation and radiates heat back into space. However, for matter, Earth is essentially a closed system with minimal mass exchange. The question asks specifically about the open system aspect, which is energy flow.

A healthy adult human heart rate is 72 beats per minute on average, with the normal resting range being 60-100 bpm. The 70-80 range is the most typical for healthy adults at rest. Rates below 60 suggest bradycardia, while rates above 100 at rest indicate tachycardia. Athletes often have lower resting rates (50-60) due to cardiovascular conditioning.