It's some change in the conditions around the organism, which the organism can detect and respond to. A change in temperature, more light, or something physically poking the organism are examples.
<span>They create energy for the cell.</span>
It is the Mid-Atlantic Ridge.
An aldehyde is an organic compound containing a group with the structure −CHO, consisting of a carbonyl<span> center </span><span>with the carbon atom also bonded to </span>hydrogen<span> and to an R group</span>
Answer:
Small intestine allow nutrients to be absorbed.