Introduction:
The developing embryo, which starts to develop from a flat sheet of cells, grows to acquire a typical cylindrical shape which takes place through the process of characteristic embryonic folding. The embryo begins to fold laterally and then folds at both the ends, forming a distinct C-shape with a distinct head and tail end.
Answer to Problem 1RAC
The correct answer is option (b) weeks 3-8 of development.
Explanation of Solution
Explanation/justification for the correct answer:
Option (b) weeks 3-8 of development. The major organ system development takes place during the 5th week of embryonic development. The neural tube starts forming, and the embryo is surrounded by amniotic fluid. The major organ system like the nervous system (brain and spinal cord) and heart are formed. So, the correct answer is option (b).
Explanation for incorrect answer:
Option (a) week 1 and 2 of development. The major organ system is not developed during 1st and 2nd week, as the zygote gets implanted during the first two weeks and forms embryonic and placental structures. So, this is an incorrect option.
Option (c) weeks 8-20 of development. During 8-20 weeks of development most of the organ systems have been formed, and the nerve centers start forming senses through rapid brain growth. The layers of skin also start to form. So, this is an incorrect answer.
Option (d) the last 30 weeks of development. During last 30 weeks of development the brain of the fetus is still growing, and the red blood cells start to form in the bone marrow, and the bones also start to harden. So, this is an incorrect answer.
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Chapter 29 Solutions
Seeley's Anatomy & Physiology
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