Alexia is testing the effect of adding salt on the conductivity of distilled water. To do this, Alexia took 5 beakers and filled them each up with 50mL of room temperature distilled water. She added 0g of salt to beaker 1, 10g to beaker 2, 20g to beaker 3, 30g to beaker 4 and 40g to beaker 5. She stirred each beaker for 10 seconds and then measured the conductivity. What is the independent (testing) variable?

A Group of answer choices

B the amount of salt in each beaker

C the beaker with no salt

D the conductivity of the beaker

the length of time she stirred the beaker

Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?

Which sentence best describes the relationship between chlorophyll and the chloroplast? a.) chlorophyll is a chemical found in a chloroplast. b.) chloroplast is a chemical found in a chlorophyll. c.) both chlorophyll and chloroplasts are found in animals. d.) both chlorophyll and chloroplasts make carbon dioxide.

What causes darkening of the skin as melanin production increases