Answer: Segmental duplication
Explanation:
Most of the times, segmental duplicarions occurs to preserve/conserve important regions on the chromosome to avoid extinction. If perhaps a damage occurs in one particular region that has a duplicate, the duplicate is present to help conserve the functions of the damaged regions.
Any formation in which groundwater rises on its own, under pressure, is called artesian well.
Answer: sagittal plane
Explanation: sagittal plane is one of the body planes,the others are coronal and transverse.
The sagittal plane divides the body into left and right portions.
Dividing the body into plans is important in the study of anatomy as it helps in precision of the part of the body under consideration and it prevents errors.