A scientist wants to investigate how the availability of
water affects the growth of trees.
Which investigation could the scientist use to gather evidence
relating to this topic?
OA. A comparative investigation in which the scientist
compares the root structures of two different types of
trees to see how they absorb water differently
B. A descriptive investigation in which the scientist closely
studies and describes the process by which trees take
in water
c. An experimental investigation in which the scientist
gives a tree a different amount of water each day and
records its growth over time
D. An experimental investigation in which the scientist
gives several trees of the same species varying
amounts of water over a period of time and measures
how quickly the trees grow
SUBMIT

C is the second best answer, but it is not compared to anything, so you don't know if the tree is acting well in the environment, or not so good at all.

D is the best answer. Take a bunch of trees. Treat them the same way and see what the range is. If it's narrow, then the scientist has not learned that much except that the trees tend to act the same way under the same conditions. If there is a lot of variation, then he or she has to devise another experiment to find out why.