Answer:
Rapid eye movement sleep (REM) may be defined as the the phase of the sleep that are unique to the mammals. This sleep is marked by the muscle tone.
The REM leads to the increase in pressure with deprivation. This leads to the increase in the rapid eye movement and plays an important role in the REM sleep and dreaming of the individual and quite necessary in the adult.
The correct answer is c. Heterotrophs compete for the same food source.
As it can be seen from the image of the food web, the tree or plants which are autotrophs are consumed by various heterotrophs. Autotrophs provide as a source of food for several heterotrophs but several heterotrophs depend on other heterotrophs such as smaller insects or animals for their food. As shown in the food web, both frog and lizard are consumers of insects so both being heterotrophs are competing for the same source of food which is insect here.
Viruses consist of two key elements- a nucleus acid molecule and a protein coat.