When you touch an object that is very hot you quickly pull your hand back. What is the correct pathway of nerve impulses for this behavior?
A. Heat receptors in the hand, motor neurons, hand muscles, sensory neurons, brain.
B. Hand muscles, motor neurons, brain, sensory neurons, heat receptors in hand.
C. Brain, sensory neurons, heat receptors in hand, motor neurons, hand muscles.
D. Heat receptors in the hand, sensory neurons, brain, motor neurons, hand muscles.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

What two fields of study provide the core information that is used to classify organisms?

Explain why it’s important for scientists to study the sun. list at least two challenges researchers face when examining earth’s nearest star.