What is the main function of the ozone layer?
a. to provide cloud cover for protection of polar regions
b. to provide a source of oxygen for photosynthesis
c. to filter toxins from acid rain
d. to block most of the sun's damaging rays from reaching Earth
e. to trap carbon dioxide and warm the planet
ANSWER: d
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Before plowing a field, a farmer thought the bare field looked weed-free. Three days after plowing and turning over the soil, he was amazed to see thousands of tiny seedlings. What is the most likely reason for the mass germination of seeds?
A) large seeds that needed soil disturbance to germinate B) small seeds that need light to germinate C) small seeds that were scarified by exposure to plow D) large seeds that needed exposure to higher levels of oxygen to germinate
What is a characteristic of the cell walls of mature plant cells?
a. pectin b. cellulose c. glue-like polysaccharides d. lignin e. a gluey matrix containing rope-like strands
When the cork cambium divides, it produces cork cells toward the inside. Indicate whether the statement is true or false
Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. What is the probability that their next child will be an albino girl?
A) 1/8 B) 1/2 C) 1/3 D) 1/4 E) 3/4