39. Which of the following signals indicates shade to a plant? A) lower temperat

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39. Which of the following signals indicates shade to a plant? A) lower temperature B) blue light C) far-red light D) green light 40. Each pollen grain contains a. a haploid tube cell and a haploid gencrative cell b. four diploid microspores c. the egg cell and the triploid endosperm d. one diploid microsporocyte and two haploid sperm cells 41. What is NOT true about the carpel of a flower? A) The stigma receives the pollen. B) The style provides the pathway for the growth of the pollen tube. C) Mciosis of the megaspore forms the eight nuclei of the embryo sac. D) The ovary encloses the ovule 42. A parent with an SiS2 genotype exhibiting sporophytic self-incompatibility can potentially fertilize which of the following plant genotypes of the same species with pollen grains? A) S3S4 B) S2S3 C) SIS3 D) S1S4 43. A summer occupation in the Corm Belt states is de-tasseling the corn: removing unwanted male flowers so that female flowers on the same plant are pollinated by the desired pollen for the hybrid corn. What does this tell you about com? A) The flowers are perfect and the plant is dioecious. B) The flowers are perfect and the plant is monoecious C) The flowers are imperfect and the plant is dioccious. D) The flowers are imperfect and the plant is monoecious. 44. Most plants are adept at asexual reproduction. What is the probable explanation for the energy spent for sexual reproduction? A) Photosynthesis produces so much sugar and oxygen, they need to be used B) Sexual reproduction ensures that the same genes will be passed on to offspring C) Sexual reproduction mixes up genes, contributing to variation in a species D) Sexual reproduction is a sign of good health of the organism

Explanation / Answer

39. Ans a) Cold temperatures can mean shade to a plant

40. a) Each pollen grain contains a haploid tube cell and a haploid generative cell

41. c) Meiosis of the megaspore forms the eight nuclei of the embryo sac.

Carpel usually is composed of Overy, stigma, style. Megaspore is present inside each ovule

42. a) S3S4

Sporophytic self compatibility is the inability to fertilize plants with similar genotype. So S1S2 plants producing S1 and S2 haploid spores should be compatible only with S3S4 plant with S3cand S4 haploid spore

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