Let's understand how a virus spreads and affects us:---Step 1: A person with a cold (caused by a virus) sneezes without covering their mouth. Tiny droplets containing virus particles fly into the air.---Step 2: Another person nearby breathes in these droplets. The virus particles enter their body, often through the nose or mouth.---Step 3: Inside the new person's body, these virus particles find suitable living cells (like cells in the throat or lungs).---Step 4: The virus attaches itself to a cell and injects its genetic material (like a tiny instruction manual) into the cell.---Step 5: The cell, following the virus's instructions, starts making many copies of the virus instead of doing its normal job.---Step 6: These new virus copies burst out of the cell, often destroying it, and then go on to infect more cells in the body.---Step 7: The new person starts feeling sick with symptoms like a runny nose, cough, or fever, because their body is fighting off the virus.---Answer: This process shows how a virus, though tiny, can multiply quickly inside a host and cause illness.