So I see at least three answers here that could potentially be correct, however I believe the best possible answer would be D. they distribute heat around the planet and are a major factor influencing the climate around the globe.
(The other two possibly correct answers would be A. and B. Animals such as Sea turtles will use the ocean currents as a means of quicker transportation and navigation. Sailors would also use the currents as a means of quicker transportation and navigation, however that is not required today with modern technological advances.)<span />
The concept of cell signaling is helpful to other fields as they listen to what is signaling them and form a unified action plan.
Human evolution known to be a process in which species adapt to certain conditions of life, and in the battle of life and death, they are forced to become stronger in order to survive in this world. Diseases have always been present during the evolution, acting themselves as a natural selectors - the weaker organisms get sick and die. Not just humans, but all species have to establish a great protecting mechanism in order to survive. That is how our bodies are built, to be able to withstand and survive in the conditions we live in, and that is why our immune system has to be taken care of.
The anterior rami of the brachial plexus are the continuations of the anterior rami of spinal nerves C5-T1 . These rami emerge from the intervertebral foramina and travel through the neck. The five rami unite to form the superior, middle, and inferior trunks in the posterior triangle of the neck. Nerves C5, C6 unite to form the superior trunk; nerve C7 remains as the middle trunk; and nerves C8,T1 unite to form the inferior trunk. Portions of each trunk divide deep to the clavicle into an anterior and a posterior division. These primarily contain axons that innervate the anterior and posterior parts of the upper limb. Upon reaching the axilla, they converge to form three cords.