How have astronomers formed their ideas about the layers of the sun? O developing mathematical models based only on known data
O making direct observations of the sun's layers
O observing all the layers during total solar eclipses
O using theoretical models combined with known data

endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.

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.