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One way to determine net and gross primary productivity in a freshwater ecosystem is to first take equal-volume samples of pond water. Determine the dissolved-oxygen content of each. Expose one sample to light and one sample to zero light. Leave the samples alone for 24 hours; measure the dissolved-oxygen content again, and determine the differences in dissolved-oxygen content. The first difference is gross productivity; the first minus the second is net productivity.

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what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave

c. the initial amount of money placed in the savings account