When jacob starts running, his legs move faster and his heart rate increases. which types of muscles are involved in these changes?
a.) skeletal muscles control his leg movement and smooth muscles control his heart rate.
b.) skeletal muscles control his leg movement and cardiac muscles control his heart rate.
c.) smooth muscles control his leg movement and cardiac muscles control his heart rate.
d.) skeletal muscles control both his leg movement and heart rate.

The most appropriate answer would be option B.

The voluntary movements such as leg movements, movement of hands, posture et cetera are controlled with the of skeletal muscles. These are striated muscles which are controlled with the help of the somatic nervous system.

The heart rate is regulated with the help of the autonomic nervous system which controls the cardiac muscles. Cardiac muscles are a special type of striated muscles which constitute the heart tissue.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.