Describe the amount of impact that using sunscreen has on vitamin d production.

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Which of the following describes a difference when gram-positive bacteria are compared to gram-negative bacteria?

Which number represents a basic ph, 4 or 9? numerical answers expected! answer for blank 1: i'll give