<span>(4) active transport
</span>Active transport is the movement of molecules across a cell membrane in the direction against their concentration gradient, i.e. moving from an area of lower concentration to an area of higher concentration.
Answer:
Muscles contract rapidly to produce heat on a cold day.
Explanation:
Adaptions to collect and retain water - thick, non-pourous stems, not leaves, but thick lobes and the ability to store water until its needed.