In cross-sectional studies, the midlife period is characterized by

increases in environmental mastery.

Explanation:

Cross-sectional study is defined by observational research, which analyzes data collected over a period of time. This survey can be in a sample population or in a predefined subset. This type of study is also known as cross-sectional study, cross-sectional study and prevalence study. The data collected in the cross-sectional study are from similar people in all variables. Except for the variable being studied.

Regarding middle age, cross-sectional studies are characterized by increases in the environmental domain as a shared feature among participants and research in this approach.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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answer; i believe the answer is hydraulic action;