The electromagnetic spectrum is divided into seven ranges of wavelengths. Is it the only part visible to the human eye.
or
is it the part visible to the human eye unless it rains.

Did the vinegar diffuse all the way to the center of any of the cubes? if so, which ones? what does this tell you about surface area-to-volume ratio and the diffusion rate?

Each member of a class sampled a piece of ptc testing paper. thirty people sampled the chemical. twenty persons were tasters. how many had heterozygous genes? 10 20 0-20 indeterminate

What determines whether a particular cell is able to respond to a hormone?