It is a true or false questions 17. Cnidarians have surface cells called choanoc
ID: 270742 • Letter: I
Question
It is a true or false questions 17. Cnidarians have surface cells called choanocyt es that contain prey capturing structures known as nematocycts. 18. The coelom of most deuterostomes develops from outpocketings of the endoderm of the gut. 19. Torsion is a unique characteristic of all mollusks. 20. Fishes may rely on their lungs for buoyancy 21. Sessile animals are often filter feeders 22. Fruits are expanded anthers. 23. During double fertilization, one sperm nucleus unites with the micropspore mother cell. 24. Coenocytic fungi have many nuclei in one extensive cytoplasm. 25. Segmentation allowed the development of specialized appendages. 26. Animals that have nerves always have brains. 27. Mollusks have closed circulatory systems 28. You could kill a starfish by cutting off its arms 29. Reptiles never have gill slits. 30. The heart of an adult amphibian has three chambers.Explanation / Answer
Answers:
17.False :
18.True
19.False.
20.True
21.False.Fruits are expanded ovary
22.True
23.False: The microspores, or the pollen, contain two cells: the pollen tube cell and the generative cell. The pollen tube cell grows into a pollen tube through which the generative cell travels. The germination of the pollen tube requires water, oxygen, and certain chemical signals. As it travels through the style to reach the embryo sac, the pollen tube’s growth is supported by the tissues of the style. In the meantime, if the generative cell has not already split into two cells, it now divides to form two sperm cells. The pollen tube is guided by the chemicals secreted by the synergids present in the embryo sac, and it enters the ovule sac through the micropyle. Of the two sperm cells, one sperm fertilizes the egg cell, forming a diploid zygote; the other sperm fuses with the two polar nuclei, forming a triploid cell that develops into the endosperm. Together, these two fertilization events in angiosperms are known as double fertilization
24.Ture
25.Ture
26.False: Examples, sea stars, sea urchins, sea lillies, sea cucumbers, brittlestars have no brains but having nerve system.
27.False. They have open circulatory system where blood pumps towards hemocoel.
28. False: starfish has a great regeneration power so cutting off it's arms won't kill it.
29. False: reptiles are chordates they do have Gills
30.True.
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