To balance the equation a coefficient of _needs to be in front of_
KCIO4 - KCl + O2

There needs to be a 2 in front of O2.

Explanation:

That would make 4 oxygen atoms and would balance the number of atoms and mass on each side. And, in a balanced chemical equation, mass and atoms are always conserved.

your answer should be c) enjoy!

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.