Reaction which breaks down complex molecules into simpler ones n release energy
The nervous system helps:
Receptors in muscles provide the brain with information about body position and movement.
The brain controls the contraction of skeletal muscle.
The nervous system regulates the speed at which food moves through the digestive tract.
The nervous system regulates respiratory rate
The nervous system regulates heart rate and blood pressure.
Source: https://faculty.washington.edu/chudler/organ.html
Segmented digestive system, appendages are animal characteristics.
Animals are a major group of organisms, classified as the kingdom Animalia or metozoa. Animals have several characteristics that set them apart from other living things. They are all eukaryotic and usually multicellular, which separates them from bacteria and most protists. Different animals differ in their own characteristics such as appendages, segmentation among other animal characteristics.
The answer is All of the above
It is the variable being controlled/changed to see if there are any effects on the dependent variable (the thing getting tested/measured)