Answer:
oligodendrocytes
Explanation:
Glial cells are part of the nervous system. These are helper cells that support the function of the central nervous system (CNS) and can be called oligodendrocytes when they supply myelin to neurons. These cells are responsible for producing the myelin sheath have the function of electrical insulator for CNS neurons. They have extensions that wrap around the axons, producing the myelin sheath.
It is estimated that there are 10 glia cells in the CNS for each neuron, but because of their small size, they occupy half the volume of nervous tissue. They differ in form and function and they are: oligodendrocytes, astrocytes, Schwann cells, ependymal cells, and microglia.
Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
A food web does not represent all the links in an actual ecosystem.
Explanation:
A food web is also called food cycle. It is understood by the natural interconnection of chain and their graphical representation. The concept is given by Charles Elton. He mentioned about the concept of food cycles in Animal Ecology but later this food cycle is replaced by food web.
Food web are limited representation of eco system. Ecologists can keep together all life forms broadly into one of the two categories which is called tropic levels. These two categories are autotrophs and heterotrophs