Question

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24. Which of the following statements concerning the loss of hind limbs during whale evolution is NOT true? a) The loss is well documented by a series of transitional fossils. b) It explains why modern whales have vestigial pelvic girdies. c) This evolutionary process involved changes in the sequence or expression of Hox genes. d) The loss of limbs by snakes is a similar adaptation to a similar environment. 25. Developmental genes are a) usually highly variable. b) never expressed. c) usually highly conserved. d) found mainly in the mitochondrial genome 26. lodine deficiency promotes the formation of enlarged thyroid glands (goitre) because a) more thyroid hormones are now produced in the thyroid gland. b) the thyroid gland switches to production of a different hormone. c) reduced levels of thyroid hormones fail to prevent stimulation of thyroid gland by TRH and TSH. d) lodine now needs to be synthesized in the thyroid gland. 27. An unequal distribution of lons inside and outside of a nerve cell is essential for generating its resting membrane potential. At rest there is a) a higher concentration of K+ inside the cell b) a higher concentration of K+ outside the cell c) a higher concentration of Na- inside the cell. d) a higher concentration of Cl-inside the cell. 28. During an action potential a) Na+ transitorily flows into the cell. b) Na+ transitorily flows out of the cell. c) K+ transitorily flows into of the cell. d) no ions flow into or out of the cell. 29. Hair cells in the inner ear are activated a) by attachment to middle ear bones b) by vibrating fluid in the inner ear. c) by attachment to the tympanum. d) by hair-like extensions from adjacent cells. 30. The sympathetic division of the autonomic nervous system a) prepares the body for action fight or flight"). b) promotes digestion and self-maintenance rest or digest c) controls voluntary movements. d) relays sensory information from the internal organs. 31. Gram staining is based on a) the ability of the bacterial cell wall to retain crystal violet dye b) the lysis of bacterial cells c) differences in bacterial shape and size d) growth of bacterial cells PTO

Answer 1

249) This evolutionary process wolutionary process involved changes Blajuence or expression of hox genees 259) Hewelly highly consvered 269 Beduad levels d thuroid baymones fail to prevent stimulation of thyroid gland by ISH & TRH. Reason: low amount of thyroxine Cone of the a thyroid harmones in the blood due to lack of dietary iodine to make it gives rise to high levels of thyroid stimulating Scharmone (TSH) which stimulates the thyroid gland 21 6 A higher concentration of Kt outside the 28a) Nut transitority flows into the cell, 29 b) by vibrating fluid in the inner car. 30a Prepares the body for action fight or fight) 312 the ability of the bacterial cell wall to cs Scannerubain crystal violt dye. CamScanner

Gram staining is based on the ability of bacteria cell well to relaining the crystal violet dye during solvent treatment. The cell walls of Gram tre microorganisms have a higher peptidoglycan and lower lipid content Scante anith grain - veyactuia, Bacteria cell walls CamSesoner stained by cryslal violet.