What do you mean by universal signs? What do you mean by universal signs? Chemicals are labeled with necessary symbols according to their classes to store or distribute them. A... Md. Saifur Rahman
What kind of substance is color? What kind of substance is color? Color is not a substance in the traditional sense. It is a perception that is created by the brai... Md. Saifur Rahman
Why is chemistry called central branch of science? Why is chemistry called central branch of science? Chemistry is called the central science because it is the foundation of many other scient... Md. Saifur Rahman
