Look at the way honeycreepers evolved. If a new species of
honeycreeper were discovered,
and it had a short, straight beak,
which bird would
likely be its closest living
relative?
• Kaua'i 'amakihi
• Tiwi
• 'Akiapola'au
• O Po'ouli

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.