Answer:
The formula for density is the mass of an object divided by its volume. In equation form, that's d = m/v , where d is the density, m is the mass and v is the volume of the object. The standard units are kg/m³.
Active transport refers to a substance moving from areas in which it has low concentration to an area with high concentration, one example i guess is endocytosis, "<span>the taking in of matter by a living cell by invagination of its membrane to form a vacuole"</span>
