What basic similarities among mammals

Q1. What basic similarities among mammals and differences between mammals (the ingroup) and reptiles (an outgroup) help support the hypothesis that all mammals share a common ancestor?

Q2. A person is to be fitted with bifocals. She can see clearly when the object is between 43 cm and 1.5 m from the eye. The upper portions of the bifocals should be designed to enable her to see distant objects clearly. What power should they have? Reply in units of dioptres.

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