Respuesta :
Answer:
By the 5th week
Explanation:
"By the fifth week of pregnancy, the blastocyst (no larger than a pencil tip) is an embryo, with a brain, spinal cord, heart, and other organs."
Answer:
By the 5th week
Explanation:
"By the fifth week of pregnancy, the blastocyst (no larger than a pencil tip) is an embryo, with a brain, spinal cord, heart, and other organs."