Astudent designs an experiment to test substances x, y, and z, to determine which one is a catalyst for the reaction: a + b ® c. only one of the unknown substances is a catalyst, and the others are nonreactive with a, b, or c.
when 10 ml of a is added to 10 ml of b, the reaction takes twenty seconds. bubbles form when the product c is created.
the student prepares three test tubes, each containing both reactants a and b. she adds unknowns x, y, and z to test tubes 1, 2, and 3, respectively. she then times the reaction in each test tube from the point when the unknown is added until bubbling stops.

the most common energy conversion is from kinetic energy to potential energy, and then from potential energy to kinetic energy.

later on comes the heat energy, mechanical energy, and other energy conversions.

this energy conversion is so common that we can find it in our day to day lives as well.

- one of the most common energy conversions involves the changing of potential energy to kinetic energy or kinetic energy to potential energy

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."