One reason that electric power plants do not send out electrical energy as a direct current is that direct current can not be transformed explain why

This is because direct power has no pulsation (waveform characteristic) that is significant in electromagnetic induction. The gradual increase and decrease of power, at a given frequency, in indirect power is significant in electromagnetic induction. This enables transformers to induce electricity into the secondary coil, from the primary coil, at the core of the transformer.Transformers transform electric power by increasing or decreasing the voltage and current of electricity.

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.