Sympathetic innervation of the heart a: increases the heart rate. b: decreases the heart rate. c: increases the force of contractions. d: decreases the force of contractions. e: has no effect on contraction force.

Option A

Explanation: The cardiovascular system is the system of human body which circulates blood through the complete body to supply oxygen to the whole body.

It also carries nutrients along with the blood and carries waste materials from the body to the heart.

Heart rate can be defined as the number of times the heart beats per minute and it is related to the load the heart has.

The sympathetic nervous system of the body releases hormone like epinephrine, nor epinephrine which increases the heart rate. There are many other factors that increase the heart rate such as exercise, stress et cetera.

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measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.