Scientific experiments are specially designed to test explanations for an observed phenomenon. a student decides to conduct an experiment to determine the effect that the amount of time spent in the sunlight has on the overall growth of a plant. the student will conduct the experiment using two identical plants that will only spend different amounts of time in the sunlight. all other aspects needed for growth will remain identical for each. in the experiment described, what would the amount of water given to each plant be considered?
a.
an observation
b.
a dependent variable
c.
an independent variable
d.
a control or constant
select the best answer from the choices provided
a
b
c
d

Alaska and northern canada have a diet rich in vitamin d and their skin color is darker than predicted on the basis of iv intensity at their latitude. explain the observation:

You have been asked to lead a demonstration for the undergraduate microbiology lab course about the uses of negative staining when studying bacteria. a "negative" stain does not stain the bacterial cell itself but stains the space between cells. under magnification, the acidic (negativelycharged) nature of the stain will be repelled by the negatively charged bacterial cell wall and willleave the cell colorless in a stained background. negative stains are used primarily to reveal the presence of negatively charged bacterial capsules; therefore, they are also called capsule stains. encapsulated cells appear to have a halo surrounding them. the negative stain procedure does not require heat fixation, which limits any chances of alteration in bacterial cell shape and size. the bacterial suspension is added to a drop of stain, such as nigrosin or eosin, and drawn across the glass slide using a coverslip.nigrosin staining-not safranin staining-of klebsiella pneumoniae will allow for the visualization of the cell shape and the determination of the presence of a capsule.true/false

Explain why the plants cortex would serve as the best food source for animals