He<span> gave it to charity. </span>He<span> had one of his contacts on dry land take it and use it to help others.</span>
An example can be hot dogs and hot dog buns. If the price of one of them falls, it would lead to the product being cheaper which would increase sales, thus bringing the demand for the other one to be much higher.
In grammar<span>, the </span><span>past participle</span><span> of a verb is a form that is usually the same as the past form and so </span>ends<span> in '-ed'.</span>