Step 1: Understanding the Artwork and Artist: 
Atul Dodiya (born 1959) is a prominent contemporary Indian artist known for his versatile and experimental approach. His work often incorporates historical, political, and art-historical references. The work in question, "Bapu," is a tribute to Mahatma Gandhi. 
 
Step 3: Detailed Explanation: 
Atul Dodiya's works on Gandhi are not limited to a single medium. He is known for creating works that blend painting with objects. Specifically, some of his most famous pieces about "Bapu" are cabinet installations. These installations are three-dimensional constructions that house a collection of objects, paintings, photographs, and texts within a cabinet or similar structure. This form of art, which uses objects and space to create an experience, is known as installation art. Therefore, this is the correct medium among the choices. 
 
Step 4: Final Answer: 
The work "Bapu" by Atul Dodiya is famously realised as an installation, often involving wooden cabinets filled with various objects, photographs, and paintings. This makes "Installation art" the correct answer. 
Rearrange the following parts to form a meaningful and grammatically correct sentence: 
P. a healthy diet and regular exercise 
Q. are important habits 
R. that help maintain good physical and mental health 
S. especially in today's busy world