The function of pits in the walls of tracheids is
A. allowing the escape of air.
B. secretion of resin.
C. sealing off air bubbles.
D. allowing the passage of water.
E. stopping backflow of water.
Answer: D
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The pathway that a secretory protein takes from inside to outside is: rough endoplasmic reticulum, ________, Golgi complex, ________, outside the cell.
Fill in the blank(s) with the appropriate word(s).
Which pattern of diploid and haploid phases reflects the life cycle in plants?
a. alternation between haploid and diploid generations b. two haploid generations followed by a diploid generation c. one haploid generation followed by two diploid generations d. a single generation that limits the haploid state to gametes while the rest of the organism is diploid e. a single generation that limits the diploid state to gametes while the rest of the organism is haploid
Which of the following are contributing factors for hemorrhiod development?
A) bacterial infection B) dietary fiber C) aging D) chronic constipation E) pregnancy
The fossil record indicates that at one time marsupials were common to both Australia and South America, but today most South American marsupials have become extinct. The most probable explanation for marsupials being common to Australia yet not very common to South America today is that
A. South American marsupials were displaced by placental mammals when a land bridge formed between North America and South America about seven million years ago. B. marsupials were able to flourish in South America because of its isolation from other land masses. C. placental mammals are less fully developed than marsupials when born and therefore have a better chance of survival after birth. D. South American and Australian marsupials interbred. E. marsupials can survive only in warm climates like Australia.