Abiotic factors which are common to both aquatic and terrestrial habitats are A. light, rainfall and temperature. B. temperature, turbidity and light. C. rainfall, salinity and turbidity. D. turbidity, light and salinity.

Here are the answers to the questions: 7. B. temperature, turbidity and light Light and temperature are fundamental abiotic factors common to both aquatic and terrestrial environments. Turbidity, referring to the clarity of water or air (e.g., dust), can also be a significant factor in both. 8. B. numbers The diagram shows a pyramid where the number of organisms at the first level (20) is smaller than the second level (3000). This indicates an inverted pyramid at the base, which is characteristic of a pyramid of numbers (e.g., a few large producers supporting many smaller herbivores). A pyramid of energy must always be upright. 9. B. trees Given that the first level has only 20 organisms but supports 3000 organisms at the second level, the organisms at the first level must be large producers, such as trees, which can provide a large amount of biomass or energy despite being few in number. 10. C. increased competition and food shortage High birth rate, low mortality, and high immigration all contribute to an increase in population size. In a community with limited resources, an increased population will lead to greater demand for those resources, resulting in increased competition and food shortage. 11. A. encourage birth control measures To control the negative implications of population growth (increased competition and food shortage), a government measure would aim to reduce the population. Encouraging birth control measures directly addresses the birth rate, helping to curb population growth. 12. B. contractile vacuole and kidney A contractile vacuole in protists (like Paramecium) is primarily responsible for osmoregulation, pumping out excess water to maintain internal water balance. Kidneys in vertebrates perform a similar function of osmoregulation and excretion of waste products. 13. B. movement and nutrition Hydra use their tentacles to capture food particles and bring them to the mouth. They also use their tentacles for locomotion, such as somersaulting. If tentacles cannot regenerate, both these functions would be impaired. 14. A. I, II and III The organism shown is a unicellular animal-like protist (likely a Paramecium). I (Cilia): Used for movement and sweeping food, characteristic of animal-like organisms. II (Contractile vacuole): For osmoregulation, a function performed by animals. III (Oral groove/Cytostome): The "mouth" region for ingesting food, indicating heterotrophic nutrition, a key animal characteristic. Parts IV and V are nuclei, which are present in all eukaryotes, not specific to animals. 15. A. movement Part III is the oral groove/cytostome. While its primary function is feeding (ingestion of food), the cilia lining the oral groove create water currents that move food particles towards the cytostome. Therefore, "movement" in this context refers to the movement of food into the organism. That's 2 down. 3 left today — send the next one.