I NEED HELP PLEASE A researcher studies the rate of progress of a chemical reaction. The researcher fixes the temperature and pressure, varies the amount of catalyst used over a range of quantities, and observes the resulting reaction rate in each case.

Which statement BEST describes why the investigation is an experimental study?

There is more than one independent variable to study.

The researcher manipulates at least one independent variable.

It is possible to get data with a range of values of an independent variable.

There is a cause-effect relation between the independent and dependent variables.

I think the answer is The researcher manipulates at least one independent variable. Hope this helps.

Step-by-step explanation:

answer

d. 10

explanation

the distance from point y to wx is the height of the triangle.

using pythagoras theorem,

group similar terms to get,

this implies that,

take positive square root of both sides to get,

this implies that,

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.