Ahigh concentration of h makes something and a low concentration of h makes something

Which of the following is an oxidation-reduction reaction? (pictured below)

The unique structure of the neuron is dedicated to the efficient and rapid transmission of neural signals. the relationship between neurons, the spinal cord, and the brain constitutes an elaborate communication system throughout the human body. all but one of the functions listed below are a result of this interaction.

Based on the topographic map of mt. st. helens, what is the contour interval of the volcano about height is 2,950 m?