Ancient photosynthetic prokaryotes were very important in the history of life because theya. produced the oxygen in the atmosphere.b. are the oldest-known archaea.c. were the first multicellular organisms.d. showed that life could evolve around deep-sea vents.

What two conditions must be present for osmosis to occur?Integral membrane proteins are anchored in lipid bilayers.

How does the hydrolysis of ATP result in the movement of a motor protein along a cytoskeletal filament?

Large-scale, worldwide adaptive radiations have occurred in which of the following situations?(A)when there are no available ecological niches(B)after each of the big five mass extinctions(C)after colonization of an isolated island that contains suit-able habitat and few competitor species(D)whenever an evolutionary innovation was needed for or-ganisms to thrive

Adaptive radiations can be a direct consequence of three of the following four factors. Select the exception.a. vacant ecological nichesb. genetic driftc. colonization of an isolated region that contains suitable habitat and few competitor speciesd. evolutionary innovation

Which of the following groups of amino acid residues (see Ch. 3, Figure 3.2) would likely be found in the portion that crosses the lipid bilayer? a. acidicb. basicc. polar unchargedd. nonpolar

Scientists studying the origin of life have accomplished which of the following steps?(A)abiotic synthesis of protocells with self-replicating, catalytic RNA(B)formation of vesicles that use RNA as a template for DNA synthesis(C)formation of protocells that use DNA to direct the polymer-ization of amino acids(D)abiotic synthesis of RNA's bases (A, C, G, U)

Which of the following steps has not yet been accomplished by scientists studying the origin of life?a. synthesis of small RNA polymers by ribozymesb. formation of molecular aggregates with selectively permeable membranesc. formation of protocells that use DNA to direct the polymerization of amino acidsd. abiotic synthesis of organic molecules

The animals and plants of India are very different from the species in nearby Southeast Asia. Why might this be true?a. India was once covered by oceans and Asia was not.b. India is in the process of separating from the rest of Asia.c. Life in India was wiped out by ancient volcanic eruptions.d. India was a separate continent until about 45 million years ago.