Describe briefly what happens during the first trimester of a pregnancy.

The first trimester of pregnancy last for about 12 weeks. The placenta (the organ that transports nutrients from mom to fetus) will form. During these 12 weeks the fetus will grow to about the size of a grain of rice. Fetus's blood cells are forming and circulation of the blood will begin. The mouth and throat begin to grow along with eyes.

answer; i do believe that the correct answer is ( portal of exit in the chain of transmission); good luck

the answer would be a." don't hit a home run when the game is tied"