Which statement best explains why invertebrates often have outer skeletons but vertebrates do not?
The outer skeleton provides protection, since invertebrates do not have backbones.
The outer skeleton surrounds the spinal cord, since invertebrates do not have backbones.
The outer skeleton helps invertebrates maintain homeostasis, since they lack spinal cords.
The outer skeleton helps invertebrates maintain homeostasis, since they lack membrane-bound organelles.

Where in the body can you find chemoreceptors? a. on the skin and ears, to detect pressure, touch, motion, and sound b. on the retina, to detect a single photon of light c. on the skin, to detect temperature or specific chemicals d. on the tongue and in the nose, to detect taste or odor

Whose work is most likely to be part-time and at several locations? а. physical therapistb. sports physicianc nutritionistd group fitness instructor

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).