You observe a sample under a microscope. it is 100 µm in diameter and has a nucleus. what would it most likely be? a. a single strand of hair. b. a bacterial cell. c. an ovum (egg cell). d. a sperm cell.

The correct answer is option (C) ovum.

Ovum or the egg cell is the female gamete that fuses with the sperm to produce the zygote. An ovum is the largest cell in the human body produced by the ovaries of the female reproductive system. It approximately measures about 0.1mm which is equal to 100 µm. A nucleus is present in the ooplasm or the yolk of the ovum.

The sample under the microscope cannot be a single strand of hair or a bacterial cell as both do not contain a nucleus. Also it cannot be a sperm as they do not have a diameter measuring about 100µm. Thus, the sample under a microscope with a diameter of 100 µm and having a nucleus is typically an ovum.