Multiply by the power of the eyepiece, usually 10x.
Th answer is D its the best answer that fits the question .
An electronic pulse oximeter, which can be clipped on the bridge of the nose, forehead, on the earlobe, or to the tip of finger, determines the oxygen concentration in arterial blood. Hemoglobin is the protein complex in blood that is responsible for carrying oxygen around the body. The pulse oximeter actually measures the concentration of hemoglobin in the blood and determines oxygen concentration from this value.
The correct answer is: c. An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter.
Operons contain cluster of genes that are transcribed together into mRNA or are not expressed at all. Formed mRNA undergos splicing to create monocistronic mRNAs so that can be translated separately. Operons are more often found in prokaryotic cells but it can appear in eukaryotic cells and in viruses.