The Full Form of PCMB is Physics, Chemistry,Maths & Biology.

To become a biologist or health-care professional, you have to study a variety of scientific disciplines — biology, chemistry, physics, and math. You might have noted that the world doesn’t actually divide itself in this way. Rather, the disciplines historically have been a way of choosing a sub-class of the phenomena that occur in the world and looking at a particular aspect of them with a particular purpose in mind. Different disciplines have different sets of tools and ways of knowing. Looking at something from different disciplinary perspectives adds a richness and depth to our understanding — like taking two 2-D pictures and merging them into a 3-D image.