To solve this problem, we need to analyze the given statements about histones and identify the incorrect one. Let's examine each option:$\newline \bullet$Option 1: Histones are organized to form a unit of 8 molecules.$\newline$ - This statement is correct. Histones form an octamer, which consists of two copies each of four different histone proteins (H2A, H2B, H3, and H4). This octamer is the core around which DNA is wrapped to form a nucleosome.$\newline \bullet$Option 2: The pH of histones is slightly acidic.$\newline$ - This statement is incorrect. Histones are actually basic proteins due to their high content of basic amino acids like lysine and arginine. These amino acids give histones a positive charge, allowing them to interact with the negatively charged phosphate backbone of DNA.$\newline \bullet$Option 3: Histones are rich in amino acids - Lysine and Arginine.$\newline$ - This statement is correct. Histones are indeed rich in lysine and arginine, which are basic amino acids. This composition is crucial for their role in DNA packaging.$\newline \bullet$Option 4: Histones carry positive charge in the side chain.$\newline$ - This statement is correct. The positive charge on histones is due to the presence of lysine and arginine, which facilitates their interaction with the negatively charged DNA.$\newline$Based on the analysis, the incorrect statement is Option 2, which states that histones are slightly acidic. Therefore, the correct answer is Option 2.