A. atom
atoms are described to be the basic unit of a chemical element.
Mainly because our lungs are made to intake air, and if we where to inhale water we would drown. oxygen can only be obtained from the air because our lungs would be able to expell the excess stuff from air easier than in water. hope i helped.
C)
The difference between allele A and allele S is due to changes in the environment.
your answer is a hope this helps
Answer: Somatosensory cortex.
Explanation: The somatosensory cortex receives all sensory input from the body. The somatosensory system is a part of the <u>sensory nervous system</u>. These sensory receptor cells are activated by different stimuli such as heat and nociception, giving a functional name to the responding <u>sensory neuron</u>, such as a thermoreceptor which carries information about temperature changes.