Help asap Which of these statements is true of the brightest stars? (1 point) O They are yellow stars.
O Many are supergiants
O Several are white dwarfs.
O Each is part of the main sequence.

Many are supergiants.

Explanation:

A star's size and core temperature determine its brightness. The brightest stars tend to be blue or blue white. Supergiants and red giants are in the region above the main sequence of stars, so that isn't true. Red are the dimmest. Yellow stars are in the middle of that spectrum. White Dwarfs are dimmer than the Sun, red giants and blue supergiants.

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.