What is true about the heterozygous sickle-cell (HbA HbS) condition? sickle-cell anemia is not expressed
sickle-cell anemia is expressed under conditions of oxygen deficiency
sickle-cell anemia is apparent in men
none of the above

a- all cells come from pre-existing cells

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.

straight probes are used primarily for measuring flow as it is approaching the test area. its geometry allows the probe to be mounted so that it is in the direct line of airflow.

true

explanation: