What is the reaction of acids with blue litmus paper? With red litmus paper?

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods. c. it shows that these organisms share the same habitat. d. it provides evidence that these organisms suffered a genetic mutation.

Which of these definitions have been paired with the correct type of cell?