[Solved] Some costs cannot be varied within a given time period.These costs are called A)overheads. B)total costs. C)fixed costs. D)variable costs. Dry Chemical: null Chemical Solutions: Homogeneous mixtures comprised of two or more substances with solutes dissolved in solvents. Anatomy: The scientific study of the structure of living beings, including their systems, organs, and tissues. Microscope: An instrument used to view objects that are too small to be seen by the naked eye.