Here are the answers to the questions: 1. The respiration organ found in the cockroach is the (B) tracheae. Insects, including cockroaches, breathe through a network of tubes called tracheae that open to the outside via spiracles. The correct answer is (B). 2. The medium for transportation of nutrients within unicellular organisms is (C) protoplasm. Unicellular organisms lack specialized circulatory systems; nutrients are distributed throughout the cell by the movement of their protoplasm (cytoplasm). The correct answer is (C). 3. The pair that consists of gametes is (A) ovum and spermatozoa. Gametes are reproductive cells. An ovum is a female gamete, and a spermatozoon is a male gamete. The correct answer is (A). 4. Hormones are transported around the multicellular body by (B) blood. In animals, hormones are secreted by endocrine glands directly into the bloodstream, which carries them to target cells throughout the body. The correct answer is (B). 5. Infective hepatitis is a disease of the (C) liver. Hepatitis is an inflammation of the liver, often caused by viral infections. The correct answer is (C). 6. The hormone that promotes secondary sexual characteristics in females is (C) oestrogen. Oestrogen (estrogen) is the primary female sex hormone responsible for the development of female secondary sexual characteristics. The correct answer is (C). 7. The term Syncarpous is used to describe a flower when the carpels are (A) many and fused. A syncarpous gynoecium has two or more carpels that are fused together. The correct answer is (A). 8. After fertilization in a flowering plant, the zygote develops into a (D) embryo. The zygote, formed after the fusion of gametes, undergoes cell division and differentiation to form an embryo within the developing seed. The correct answer is (D). 9. A flowering plant having both male and female flowers on the same plant is said to be (B) monoecious. Monoecious plants have separate male and female flowers on the same individual plant. The correct answer is (B). 10. The following that may not contribute to environmental pollution is (A) solar energy radiation. Solar energy itself is a clean and renewable energy source. While excessive UV radiation can be harmful, solar energy as a source* is not considered a pollutant in the same way as industrial waste, smoke, or emissions from nuclear power plants. The correct answer is (A). 11. The following that is a pollutant in air is (C) carbon monoxide. Carbon monoxide (CO) is a toxic gas produced by incomplete combustion and is a significant air pollutant. Oxygen, water vapor, and nitrogen are natural components of clean air. The correct answer is (C). 12. The water pollutant that may contain organisms that cause dysentery is (B) sewage. Sewage contains human and animal waste, which can harbor pathogenic microorganisms (bacteria, viruses, parasites) that cause waterborne diseases like dysentery. The correct answer is (B). 13. The failure of a species to adapt to any environment must lead to (C) extinction. If a species cannot adapt to changes in its environment, it will eventually be unable to survive and reproduce, leading to its extinction. The correct answer is (C). 14. The following that is not an adaptation of plants or animals for a desert environment is (D) broad leaves for storage. Broad leaves would increase the surface area for transpiration, leading to excessive water loss, which is detrimental in a desert. Desert plants typically have adaptations to reduce water loss, such as small or modified leaves (spines), thick cuticles, and deep root systems. The correct answer is (D). 15. The organism that does not show color adaptation to its environment is (D) earthworm. Toads and chameleons are known for their camouflage and ability to blend with their surroundings. Earthworms live underground and do not rely on color adaptation for survival or camouflage. The correct answer is (D). 16. An association between two organisms in which both benefit is called (C) symbiosis. More specifically, this relationship is called mutualism, which is a type of symbiosis where both organisms benefit. Given the options, symbiosis is the best general term that encompasses mutualistic relationships. The correct answer is (C).