Which best describes the purpose of a controlled experiment?
a. to make sure the results of the experiment support the hypothesis
b. to prevent a dangerous condition resulting from a reaction
c. to examine whether one variable causes a change in another
d. to prevent an undesired change in a variable

C. to examine whether one variable causes a change in another.

Explanation:

A controlled experiment is the one where a control variable is used which is used as a benchmark or standard for comparing the changes occurring in a dependent variable due to the changes occurring in an independent variable by undergoing manipulation and alteration.

On the basis of the above explanation, C. to examine whether one variable causes a change in another is the correct option.

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg