Answer: <u><em>D. An observation that has a number associated with it</em></u>
Explanation: The answer is D. An observation that has a number associated with it. I would explain further, but it is pretty self explanatory.
<em>Good luck!</em>
Upwelling is a process in which the deep and cold water rises to the water surface and not sea surface. This process plays an important role in maintaining balance in our ecosystem as it boost the marine productivity by washing the nutrients from deeper waters to the photic layer where photosynthesis is promoted.
With water it's the high surface tension property, combined with the fiber construction of paper towels. :)
Rather, each myelin sheath insulates the axon over a single long section and, in general, each axon comprises multiple long myelinated sections separated from each other by short myelin sheath-gaps called nodes of Ranvier. ... In the CNS, axons carry electrical signals from one nerve cell body to another.