What drives the flow of water through the xylem?
A) passive transport by the endodermis
B) the number of companion cells in the phloem
C) the evaporation of water from the leaves
D) active transport by sieve-tube elements
E) active transport by tracheid and vessel elements
Answer: C
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A group of AIDS patients and their families is exposed to the fungus Pneumocystis carinii. There is great concern among the individuals. You have been asked to address the situation. Explain what you would say to the group to give them a plausible treatment strategy.
A. Those with AIDS should not be concerned. This fungus is the cause of AIDS--they already have the fungus. B. Those with AIDS should be concerned as this fungus attacks T-cells in the same way as does AIDS and thereby increases the severity of the disease. C. Those with AIDS should not be concerned, as the fungus attacks the AIDS pathogen and thereby reduces the severity of the disease. D. Those with AIDS should be concerned as the fungus infects individuals whose immune system has been weakened by AIDS and causes pneumonia.
Which of the following are the male gametophytes in flowering plants?
a. stamens b. sperm c. shoot parts bearing male flowers d. pollen grains e. anthers
Over the past 100 million years, species richness has declined for gymnosperms and has increased for angiosperms
Indicate whether the statement is true or false
Any change in the normal nucleotide sequence that codes for an amino acid is called a ___________________________________.
mutation replication translation transcription protein synthesis