The focal length of David's lens is 40 cm. If Rebecca stands in front of David at a distance of do and David perceives the position of Rebecca at di, what does do equal if the magnification is -0.45

Apossible explanation for a set of facts that can be tested by further investigation is called

Which of the following is not am example of a polymer? protein nylon kevlar concreta

Why does karst topography exist in some geographic location? a. few climates have enough oxygen b. most regions have rock layers other than limestone c. in most regions, the soil is too thin d. the water is too acidic enough in most places