When preparing a wet mount specimen for viewing, the specimen should be covered with

Diffusion is a passive process that does not require energy input from the cell. It is driven by the random motion of molecules that results in a net movement from regions of higher concentration to regions of lower concentration.

Diffusion is one of the ways that substances can cross the cell membrane, such as oxygen, carbon dioxide, and water. Diffusion is important for cellular functions, such as gas exchange, nutrient uptake, and waste removal. Diffusion also helps maintain the homeostasis of the cell by balancing the concentration gradients of different molecules. Therefore, diffusion is the movement of a molecule from an area of higher concentration to an area of lower concentration.

Choice A rationale: Transfer pipette is correct because you need a transfer pipette to transfer a drop of water or a liquid specimen onto the center of the slide. A transfer pipette is a plastic or glass tube with a bulb at one end that can suck up and release liquids.

Choice B rationale: Clean slide is correct because you need a clean slide to place the specimen on. A slide is a thin, flat piece of glass or plastic that can be viewed under a microscope. A clean slide ensures that there is no contamination or interference from other substances.

Choice C rationale: Bunsen burner is incorrect because you do not need a Bunsen burner to make a wet mount. A Bunsen burner is a device that produces a flame by mixing gas and air. A Bunsen burner is used for heating, sterilizing, or burning substances, not for making a wet mount.

Choice D rationale: Timer is incorrect because you do not need a timer to make a wet mount. A timer is a device that measures or indicates the passage of time. A timer is used for timing experiments, not for making a wet mount.

Choice E rationale: Tweezers is correct because you need tweezers to pick up and place the specimen on the slide. Tweezers are a pair of metal or plastic pincers that can grasp and hold small objects. Tweezers are useful for handling delicate or microscopic specimens.

Choice F rationale: Cover slip is correct because you need a cover slip to cover the specimen on the slide. A cover slip is a thin, transparent piece of glass or plastic that can be placed over the specimen on the slide. A cover slip protects the specimen from drying out, dust, or damage, and creates a flat surface for viewing under the microscope.