Answer: D. Hypothesis B is more useful because it suggests a way to test the relationship between heart rate and caffeine intake.
Hypothesis A and B both are suggesting that caffeine intake is related to higher heart rate. But hypothesis B is proving it more certainly by suggesting the affects of caffeine intake on heart rate. As, heart rate of most people will be higher 30 minutes after they drink a cup of coffee is testifying the fact, that higher heart rate is related with caffeine intake.
Therefore, hypothesis B is more useful because it suggests a way to test the relationship between heart rate and caffeine intake.
Water, soil, sunlight, H20, and nutrients.
Guessing you mean "impulse".
It means to have a sudden strong desire to do something or a small amount of energy that moves from one area to another.
Hope this helps.
Answer:
it affects the hardness of the shells because calcium has a high reactivity which causes the shell to be hard
Explanation:
High melting point
Good conductors of heat and electricity
Lustrous (shiny)
Malleable (can be hammered)
