<span>Luca Cavalli-Sforza is a geneticist who hypothesized that the skin-color change came late because previous people had complete vitamin D access to the foods that they are eating. But the moment they started farming, the main vitamin sources are reduced, making a larger gain of having light skin.</span>
Answer:
a. back muscles are strong to maintain erect posture.
Explanation:
Human back muscles are categorized as superficial, intermediate and deep muscles. The intrinsic (deep) back muscles of the human back regulate the movement of spine and maintain erect posture of human.
For example, the erector spinae is the largest muscle of the human back and is present on either side of spine. It consists of iliocostalis muscles (lateral), longissimus muscles (intermediate), and spinalis muscles. Together these muscles serve in extension of the spine and maintain the erect posture of the spine.
Answer - <span>A. Pupils of the eyes dilate in the dark.
Reasoning - To start reason why it is answer A is because of the changes in the environment. Since the changes in the environment is dark, then your eyes will begin to dilate or get bigger in the dark to capture more light.
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