This biology question covers important biological concepts and processes. The step-by-step explanation below helps you understand the underlying mechanisms and reasoning.
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Hey ireenkiriungi24, good to see you again. 11. a) The meaning of the following terms used in floral biology: i) Incomplete flower: A flower that lacks one or more of the four main floral organs: sepals, petals, stamens, or carpels. ii) Actinomorphic flower: A flower that exhibits radial symmetry, meaning it can be divided into two identical halves by any plane passing through its center. iii) Zygomorphic flower: A flower that exhibits bilateral symmetry, meaning it can be divided into two identical halves by only one specific plane. 12. Lamarck's Theory of evolution is not accepted by biologists today because it proposed the inheritance of acquired characteristics. Modern genetics has shown that traits acquired during an organism's lifetime (e.g., muscle development from exercise) are not passed on to offspring because they do not involve changes to the germline DNA. Only heritable genetic variations can be passed down through generations. 13. Two types of movable joints found in mammals are: • Ball and socket joint (e.g., hip joint, shoulder joint) • Hinge joint (e.g., elbow joint, knee joint) 14. The alveolus of the lungs of a mammal is adapted to its function by: • Having a large total surface area for efficient gas exchange. • Possessing thin walls (one-cell thick) to provide a short diffusion distance for gases. • Being surrounded by a rich network of capillaries to maintain a steep concentration gradient for oxygen and carbon dioxide. • Having a moist surface to allow gases to dissolve before diffusion. 15. Let 'A' be the dominant allele and 'a' be the recessive allele. When two heterozygous pea plants are crossed (Aa x Aa), the genotypic ratio of the offspring is 1 AA : 2 Aa : 1 aa. a) How many of these seeds were likely to be homozygous? Homozygous genotypes are AA and aa. The proportion of homozygous seeds is (1)/(4) (AA) + (1)/(4) (aa) = (2)/(4) = (1)/(2). Number of homozygous seeds = (1)/(2) × 40 = 20 seeds. b) How many different genotypes are there in the offsprings? The different genotypes are AA, Aa, and aa. There are 3 different genotypes. 16. a) Name three types of cells that carry out photosynthesis. • Palisade mesophyll cells • Spongy mesophyll cells • Guard cells 17. a) What is environmental degradation? Environmental degradation is the deterioration of the environment through the depletion of resources, destruction of ecosystems, habitat loss, and pollution, leading to a reduction in the environment's capacity to support life. b) State three cases of environmental concern that have resulted from the increased human in recent years. • Climate change (e.g., global warming, extreme weather events) • Deforestation (leading to habitat loss and soil erosion) • Pollution (e.g., plastic pollution, air pollution, water contamination) 18. Explain the role of the following factors in breaking seed dormancy: a) Light Some seeds require exposure to specific wavelengths of light (e.g., red light) to trigger germination. Light can activate photoreceptors within the seed, leading to hormonal changes (like the production of gibberellins) that initiate metabolic processes required for growth, especially for small seeds that need to germinate on the soil surface. b) Soaking in water Soaking in water is crucial for breaking dormancy as it allows the seed to imbibe water, which hydrates the embryo and activates metabolic enzymes. Water also helps to soften the seed coat, making it easier for the radicle to emerge, and can leach out chemical inhibitors that prevent germination. Send me the next one 📸