Astudent wants to test the hypothesis that an acidic environment will decrease enzyme activity. in the
experiment, the student used an enzyme that breaks down hydrogen peroxide into water and bubbles of
oxygen. to test the hypothesis, the student should collect data on the number of oxygen bubbles produced
at different
(1) temperatures (3) enzyme concentrations
(2) ph levels (4) concentrations of hydrogen peroxide

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.

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.