How can we determine the velocity of a star moving toward or away from Earth? a. By looking at the color of the star. b. By the shift of its spectral lines. c. By the brightness of the star. d. By its change in apparent size.

Hello!

Your answer should be B. By the shift of its spectral lines.

Explanation:

It is known that when studying space, to tell if a star is moving TOWARDS EARTH its measurements will move towards the RED side of the Spectrum...

MOVING AWAY will mean its measurements will move towards the BLUE end!

HOPE THIS HELPS!

itsMATT04

{i did a bit of research from revision guides so there may be some similar phrases! :)}

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.