How can you change a reaction to make it have less activation energy?

Q: a: in sexually reproducing animals, once fertilization of the egg takes place, the exists as a single cell until cell division begins

The image below shows a common blood pressure gauge. what does this device do? a. measures the level of oxygen present in the blood b. measures the pressure of blood when the lungs expand and compress c. measures the electrical activity of the heart d. measures the pressure of blood when the heart contracts and relaxes

In the practice of science, this type of reasoning is used to develop explanations.