D. would be the answer because they are all within the eukaryote kingdom
The main reason why the testes are suspended within the scrotum is to provide cooler temperature for the testes and make it fertile for penetrating the egg. The Scrotum may contract or lengthen depending on the temperature of its surrounding.
A simple example is a connection between the circulatory and respiratory systems. <span>As </span>blood<span> circulates through your body, it eventually needs fresh oxygen </span><span>from the air. When the </span>blood<span> reaches the lungs, part of the </span>respiratory system<span>, the </span>blood<span> is re-oxygenated.</span>
Mastication is the process by which food is crushed and ground by teeth. It increases the surface area of foods to allow a more efficient break down by enzymes.