how soil gets affected by the repeated growing of crops in the same field how does use of fertilizers help the farmers

Repeated growing of crops in the soil decreases the fertility of the soil as the crops use up the nutrients of the soil. ... Farmers replenish the soil of the depleted nutrition with the help of fertilizers or crop rotation. Fertilizers are chemical substances that are rich in a particular nutrient.

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.