The last universal common ancestor (LUCA) probably lived about 3.5 billion years ago
a. true
b. false
Answer: a. true
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Because energy transfer is not 100% efficient across trophic levels, a maximum of about _____% of energy and biomass available at one trophic level is available at the next
A. 1 B. 5 C. 10 D. 15 E. 20
The relationship between energy and wavelength is ________
a. invariable, all photons have the same energy regardless of their wavelength b. inversely proportional, short wavelengths carry high-energy photons c. directly proportional, long wavelengths carry high-energy photons d. unpredictable and dependent on the initial speed of the photons
Nearly every eukaryotic cell
A) has its genetic material concentrated in a membrane-enclosed nucleus. B) has a cell wall composed of cellulose that serves as the outer boundary of the cell. C) contains a hard, noncompressible fluid called the cytosol. D) possesses flagella and cilia, unlike prokaryotes. E) contains all of its genetic material in mitochondria.
Why are model organisms used to test hypotheses?
A) The hypotheses are likely to apply only to the model organism. B) The hypotheses are potentially too dangerous to perform on human subjects. C) Human subjects have already been tested. D) The hypotheses have results that are always applicable to humans.