Answer:
Experimental groups: type of dogs
Dependent variable: hearth rate
Independent variable: the amount of caffeine
Explanation:
The dependent variable is the variable being measured or tested in a given study, while the independent variable isn't changed by the other variables. In this case, the heart rate is dependent on the amount of caffeine, which is then the independent variable. The experimental groups are the groups exposed to the independent variable.
My answer would be "Earthquakes happen along cracks in the earth's surface, called fault lines, and can be felt over large areas"
Answer:
Discovered that DNA was in the shape of a double helix
Answer: The given statement is true.
Explanation: Ionization energy is defined as the amount of energy required to remove an electron from the outermost shell of an isolated gaseous atom.
General equation of ionization energy is given by:

- If the outermost electron is loosely bound to the nucleus which means that the electron can be easily removed form an atom, it will require less amount of ionization energy.
- And if the outermost electron is tightly bound to the nucleus which means that the electron cannot be removed easily from an atom. And hence, it will require more ionization energy.
Hence, the given statement is true.