Lizzie loves to stargaze at night. she has noticed that the moon appears to change shape over the course of the month, and she wants to investigate why this happens. she hypothesizes that the relationship of the sun, earth, and moon creates shadows on the moon. she sets up an experiment with a light bulb to represent the sun, a large beach ball to represent earth, and a smaller foam ball to represent the moon. she researches the position of the sun, earth, and moon at different times of a month and makes a model of the entire system.

list at least three variables lizzie should control during the experiment. for each variable identified, give a specific suggestion for how lizzie can control it.

Select the correct answer.which scenario describes unethical lab behavior? a.danny stores the chemicals required for his experiment in flasks and beakers.b. anna publishes the results of her experiment on the growth rate of saplings.c. jason repeatedly runs an experiment until he gets the results he desires.d. mia records her observations of an experiment precisely and accurately.resetnext

The kidney filters potentially toxic substances in the blood, and thus “clears” the blood of those substances. this clearance function is dependent upon and proportional to the diffusion gradient of the substance across filtering capillaries, i.e. if the concentration of the substance is doubled, twice as much will be cleared from each ml of blood that is filtered. suppose that the body produces a constant amount of a substance x per unit of time. the kidneys eliminate substance x at a rate directly proportional to the concentration of the substance and the volume of blood cleared each minute (c): elimination = c × [x], where [x] is the steady-state concentration of substance x. imagine an individual with an initial concentration of x equal to [x]0 who develops kidney disease. her baseline clearance c0 drops to one half of the original (½c0). what is the new steady state concentration of x? (for simplicity, assume that substance x is 100% filtered by the kidney).

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit.there is a precise compatibility between the active site and the lactose molecule.specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed.reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.