Final answer:
A disease is any condition that disrupts the normal functions of the body. Pathogens are microorganisms or viruses that cause disease by invading and multiplying in host tissues. Vectors are organisms that carry pathogens from one person or animal to another.
Step-by-step explanation:
A disease is any condition in which the normal structure or functions of the body are damaged or impaired. It can be caused by various factors, including infection by a pathogen, noninfectious environmental causes, genetics, or inappropriate immune responses.
Pathogens are microorganisms or viruses that cause disease by invading and multiplying in host tissues, causing damage and releasing toxins. They can be transmitted through different routes, such as airborne transmission, direct contact, fecal-oral transmission, or through vectors.
In this context, a vector refers to an organism that carries pathogens from one person or animal to another. Mosquitoes and ticks are common examples of vectors that can transmit diseases like West Nile virus or Lyme disease.