Consider the following statements regarding the general symptoms of diseases and choose the correct answer:
1. The charges in the host which serve to recognise the disease are called the signs and symptoms of the disease
2. The sign of a disease is the external appearance of some portion of the pathogen of the host
3. The symptoms are the visible effects which the host plant induces on the parasites
4. Any visible deviation on the host plant from the normal structure and function is called a symptom