How do you calculate the S-P wave interval? A . Determine the difference in the arrival of the P wave and the ending of the S wave
B. Determine the difference in the arrival of the P wave and the ending of the S wave
C. Determine the addition in the arrival of the P and S waves
D. Determine the difference between the ending of the P wave and the beginning of the S wave

segmentation=endoskeleton=backbone=coelom=tissues

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.

he movement of air through earth's or any planet's atmosphere is called wind, and the main cause of earth's winds is uneven heating by the sun. this uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.

i hope this : )