Which of the following four statements, if any, is true regarding essential elements and living organisms?
a. All organisms require 25 of the 92 naturally occurring elements to survive.
b. The elements carbon, hydrogen, nitrogen, and oxygen make up 20-25% of living mass.
c. Although all forms of life require iron, other elements are required only by certain species.
d. Given their low concentrations in nature, the toxicity of some elements is generally not a factor in the evolution of biological communities.
e. All of the listed responses are correct.
Ans: c. Although all forms of life require iron, other elements are required only by certain species.
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Sex-influenced traits are expressed ____
a. aftafter the formation of a Barr body b. more in males than in females c. as a result of hormone differences between males and females d. only in males e. only in females
For the relative proportions of alleles and genotypes in successive generations to stay the same, which condition must
be met for the population? a. There can be no natural selection. b. A population must not be very large. c. There can only be mating between relatives. d. A population can only have some migration. e. A population can have only occasional matings.
During the first stage of cellular respiration, one six-carbon glucose molecule is converted to two three-carbon
A.) ATP B.) water C.) carbon dioxide D.) pyruvate
How can surgeons help to limit nosocomial infections?
A) They should perform surgeries and invasive procedures only when absolutely necessary. B) They should only operate on healthy individuals. C) They should prescribe as many antibiotics as possible. D) They should prescribe immunosuppressive drugs to their patients.