Answer:
first trimester
Step-by-step explanation:
During the first trimester, the baby's major organs begin to develop. This happens specifically in the second month of pregnancy.
The second month of pregnancy (first trimester) is especially critical for the baby's development. Any problem with drugs, viruses, or environmental factors such as pesticides can cause birth defects.
Baby's development is very rapid during the second month and by the end of this month, all major organ and systems including brain, lungs, liver, and stomach will have begun to develop. The first bone cells appear. The eyelids form and grow, but are closed immediately and the ears are formed. The ankles, big toe, wrists, toes, and sexual organ develop.