Which of the following was a challenge to the survival of the first land plants?
A) too much sunlight
B) a shortage of carbon dioxide
C) desiccation
D) animal predation
Answer: C
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What were the short-term responses of each population during the first 20 years following the removal of the prairie dogs? a. Prairie dogs remained absent, and the mesquite population level rose to dominate thecommunity landscape
b. Ferrets, hawks, forbs, and mice populations all reduced very quickly to zero or near zero. c. Grasses rose very quickly, but then began to fall. d. All of the above.
Specialized symbiotic associations between the roots of plants and fungi are called
A. a mycelial unit. B. lichens. C. hyphal associations. D. mycorrhizae. E. heterokaryotic junctions.
The Drosophila regulatory segment that defines the location of Eve stripe 2 contains binding sites for four different transcription regulators: two repressors (Giant and Krüppel) and two activators (Bicoid and Hunchback). For Eve to be efficiently expressed in stripe 2, both repressors must be absent and both activators present. What would you expect to see in flies that lack the gene that encodes Bicoid? (Assume that Bicoid does not influence the expression of Hunchback, Giant, or Krüppel.)
A. Stripe 2 would become narrower. B. All 7 stripes would disappear. C. Stripe 2 would become fainter. D. Stripe 2 would expand toward the tail of the embryo. E. Stripe 2 would expand toward the head of the embryo.
True or false: The number of polypeptides possible with 50 amino acids would be calculated as 5020
A. true B. false