What is the basic principle behind vaccine development? How do vaccines work? What approaches were adopted by the Indian vaccine manufacturers to produce COVID-19 vaccines?

Key learnings from their answer

• ›Turned abstract S&T concepts into purpose-built diagrams rather than decorative ones: a Sun-Earth Lagrange-point map (L1-L5) to locate Aditya-L1, vertical-vs-horizontal RLV contrast sketches, a Gaganyaan LEO orbit + escape-module sketch, and an mRNA flow (cell/vector -> spike protein -> immune response) paired with a PIR-vs-SIR immune-response-over-time graph -> for any S&T question, draw the actual mechanism/geometry, not a generic box-chart; the diagram should carry information the prose can't, like orbit positions or a response curve over time.
• ›Anchored almost every body point to one hard figure tied to a named source: IoT market ~$7.8 bn and +45% yield from the Dalwai Committee, ~$300 bn UPI throughput, 99.9% Aadhaar coverage, ~Rs 1.5 lakh crore JAM savings, nuclear 8.1 GW (2024) against the 100 GW goal, mRNA developed in ~10 months -> pre-memorise a few precise number-plus-attribution pairs per high-yield theme so each claim lands as evidence rather than assertion.