Take some water from a pond or fish tank and pour it into a beaker with hay. After a few days, you will find that mildew spots appear on the water surface. These mildew spots are formed by the accumulation of microorganisms that are invisible to the naked eye.
Take some water from a pond or fish tank and pour it into a beaker filled with hay. A few days later, it is found that mildew spots appear on the water surface. These mildew spots are formed by the accumulation of microorganisms invisible to the naked eye.
Take some water from ponds or fish tanks and pour it into beakers filled with hay. After a few days, it is found that there are mildew spots on the water surface, which are formed by invisible microorganisms.