A. Mobbing is a behavior that a social group of birds uses to respond to a predator threat to the entire group. B. Mobbing is a behavior that adult birds use to respond to a
predator threat to nestlings.
C. Mobbing is a behavior that immature birds use to respond to a predator threat to themselves.
D. Mobbing is a behavior that individual birds use to respond to a predator threat to themselves.

i would say the prokaryotic cells the prokaryotic cells are less complex, are usually found only in unicellular organisms and have more limited capabilities than eukaryotic cells.

amber has allowed scientists to study dna that has been preserved over millions of years.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.