Which of the following must be visually studied using microscopy?
Multiple choice.

Choice A rationale: Eukaryotes is incorrect because eukaryotes are organisms that have cells with a nucleus and other membrane-bound organelles, such as animals, plants, fungi, and protists. Some eukaryotes, such as protists, are microscopic and require microscopy to be studied, but others, such as animals and plants, are macroscopic and can be seen with the naked eye.

Choice B rationale: Fungi is incorrect because fungi are a group of eukaryotic organisms that include mushrooms, molds, yeasts, and lichens. Some fungi, such as yeasts and molds, are microscopic and require microscopy to be studied, but others, such as mushrooms and lichens, are macroscopic and can be seen with the naked eye.

Choice C rationale: Prokaryotes is correct because prokaryotes are organisms that have cells without a nucleus or other membrane-bound organelles, such as bacteria and archaea. All prokaryotes are microscopic and require microscopy to be studied. Prokaryotes are the smallest and most abundant living organisms on Earth.

Choice D rationale: Plants is incorrect because plants are a group of eukaryotic organisms that have cells with a cell wall, chloroplasts, and a large central vacuole, such as mosses, ferns, and flowering plants. Some plants, such as mosses and algae, are microscopic and require microscopy to be studied, but others, such as ferns and flowering plants, are macroscopic and can be seen with the naked eye.

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration across a semi-permeable membrane. Diffusion stops when there is no net movement of particles across the membrane, which means that the rate of diffusion in one direction is equal to the rate of diffusion in the opposite direction.

This does not necessarily mean that there is an equal concentration of particles on both sides of the membrane, but rather that there is a dynamic equilibrium between the two sides. For example, if a semi-permeable membrane separates a solution of 10% sugar and 90% water from a solution of 20% sugar and 80% water, diffusion will occur until the sugar concentration on both sides is 15%.

However, if the membrane only allows water to pass through, diffusion will occur until the water concentration on both sides is equal, which means that the sugar concentration on one side will be higher than the other. Therefore, diffusion does not always result in an equal concentration of particles on both sides of a semi-permeable membrane.