Gradient should be in the blank, hope that helps
I believe it is either fish of plants (Most likely plants).
The short plants<span> are </span>not able<span> to </span>compete<span> with </span>tall plants<span> for </span>sunlight<span>. ... The </span>tall plants, however, aremore susceptible<span> to </span>wind damage<span>. Which </span>type<span> of </span>selection<span> are the </span>plants experiencing? directionalselection<span> ... They are believed to have come from </span>one<span> common ancestor and just become </span>more<span> and</span>more<span> different due to .</span>
The main difference is that quotas restrict quantity while tariff works through prices
