Answer:
The mucosa, or mucous membrane layer.
Explanation:
It is the innermost tunic of the wall. It lines the lumen of the digestive tract. The mucosa consists of epithelium, an underlying loose connective tissue layer called lamina propria, and a thin layer of smooth muscle called the muscularis mucosa.
Hope I helped! :)
The right answer has to do with birth defects and in this case the defect wouldn't be hereditary nor genetic so i think the best answer is (D) underdeveloped lungs
15. C
16.B
17.H
18. A
19.E
20.D
21.G
22.F
I think this is correct sorry if any are wrong