A microbiologist used Gram staining method in a laboratory to identify different types of infectious bacteria in four different samples (I, II, III and IV). The given table shows the results.Based on given results, gram positive bacteria are found in samples:

Explanation

Gram staining is a method used to differentiate bacterial species into two groups based on the chemical and physical properties of their cell walls. Gram-positive bacteria retain the crystal violet stain and appear purple under a microscope. In this question, to identify which samples contain gram-positive bacteria, you must refer to the staining results. Samples II and III exhibit the characteristics of gram-positive bacteria, while Samples I and IV do not, as they are gram-negative, which shows a red-pink colour. Therefore, the correct answer is Sample II and III.