the answer is C. light and heat
Sorry this will probably be pretty long.
So think of the "control" as being something you yourself add to increase or decrease the effects in an experiment.
I'll give you an example so it is not as confusing.
Say you have decided to make an experiment on plants. Which plant can grow the fastest on which type of liquid? What is being added to this experiment? The liquid! Or all of the liquids you used. Like if you used Coke, Lime Gatorade, Orange Gatorade, and Water. Each drink will EFFECT each plant differently.
Hope I was of any hope?
Answer
Sounds travel slowest in gasses so it would be air
A is your answer The ratio of females to males
Answer:
Explanation:
= Half-life of carbon = 5700 years
t = Time at which the remaining mass is to be found = 10400 years
= Initial mass of carbon = 11 g
Decay constant is given by

Amount of mass remaining is given by

The amount of the substance that remains after 10400 years is
.