(I am not a doctor, but) according to www.pregnancy.org, by nine weeks (first trimester) the fetus can flex its limbs and digits, which would be impossible without muscle tissue.
1st trimester- all of the baby's body structures and systems develop 2nd trimester- marked by the grown and masturbation of the fetus's organs and body systems. 3rd trimester- the fetal systems continue to grow and mature also the time of the greatest weight gain
The first trimester is most critical for the development of a baby. The babies brain is formed during the first trimester.
Body parts are formed.
Body parts are formed.
second trimester
The major organs systems have started developing.
It is a muscle in formed in the skull.
digestion
Pregnancy is broken down into three trimesters. The baby develops most rapidly during the first trimester (weeks 1-13). The baby starts off as a collection of cells that develop into an embryo. At 8 weeks, the embryo is called a fetus because the baby resembles a human. At this time, all major organs and systems have been formed. During the second trimester (weeks 14-26), the organs and systems start to mature. During the third trimester (week 27-40), the baby starts to pack on the pounds.
Muscle
Muscle
your tricep and bicep will be apart of your upper muscle