Students are observing two families of ducks living in the school pond. They decide to do a scientific investigation that involves the ducks. The students have only one class period to complete the investigation. Which of the following is a valid hypothesis the students could investigate? A.
Ducklings think humans are funnier than adult ducks do.
B.
Ducks first came to the pond due to its high level of water quality.
C.
Ducklings will likely move to a new pond when they are fully grown.
D.
Ducks from different families will not feed within 10 feet of one another.

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna.

What is the problem in this article? what solution does the article propose?

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).