Cancer causing agents are called carcinogens. They are physical, chemical agents, ionizing radiations and biological agents.
i) Physical Irritant: Heavy smoking causes lung cancer and cancers of oral cavity, pharynx (throat) and larynx. Betel and tobacco chewing causes oral cancer. Excessive exposure to sunlight may cause skin cancer.
ii) Chemical agents: Nicotine, caffeine, products of combustion of coal and oil, pesticides, asbestos, nickel, certain dyes and artificial sweeteners induce cancer.
iii) Radiations: Ionizing radiations like X-rays, gamma- rays, radioactive substances and non-ionising radiations like UV rays cause DNA damage leading to cancer.
iv) Biological agents: Cancer causing viruses are called oncogenic viruses.

Cancers are classified into three types based the tissues from which they are formed.
i) Carcinomas arise from epithelial and glandular tissues. They include cancers of skin, lung, stomach and brain. About 85% of the tumours are carcinomas
ii) Sarcomas are occur in the connective and muscular tissue. They include the cancer of bones, cartilage, tendons, adipose tissue and muscles. These form 1% of all tumours.
iii) Leukaemia are characterized by an increase in the formation of white blood cells in the bone marrow and lymph nodes. Leukaemia are called blood cancers. Most common type of cancer which also affect children below 15 years of age.

Prevention and control of diabetes.
i) Dietary management:
a) Low carbohydrate and fiber rich diets are more appropriate.
b) Refined sugars (Sucrose and glucose) should be avoided.
c) Diet comprising whole grains, millets (Gjowar, bajra, ragi), green leafy vegetables, wheat and unpolished rice should be included in diet regularly.
d) Saturated fat intake should be reduced. Polyunsaturated fatty acid content should be higher.
ii) Management with insulin: Commercially available insulin preparations (short and long acting) are also used to maintain blood glucose levels.
iii) Physical activity: Exercise plays an important role in facilitating a good control of diabetes, in addition to strengthening and toning up the muscles.
iv) Education and Awareness: People with diabetics should be educated on the nature of disease they have and the possibility of complications of the disease, if blood sugar is not kept under control. Instructions regarding diet, exercise and drugs should be explained.

i) Diet management: Reduction in the intake of calories, low saturated fat and cholesterol rich food, low carbohydrates and common salt are some of the dietary modifications. Diet rich in polyunsaturated fatty acids (PUFA) is essential. Increase in the intake of fiber diet, fruits and vegetables, protein, minerals and vitamin are required.
ii) Physical activity: Regular exercise, walking and yoga are essential for body weight maintenance
iii) Addictive substance avoidance: Alcohol consumption and smoking are to be avoided.

Diabetes mellitus is associated with several metabolic alterations. The most important symptoms are
i) Increased blood glucose level (Hyperglycemia) 
ii) Increased urine output (Polyuria) leading to dehydration
iii) Loss of water leads to thirst (Polydipsia) resulting in increased fluid intake
iv) Excessive glucose excreted in urine (Glycosuria)
v) Excess hunger (Polyphagia) due to loss of glucose in urine.
vi) Fatigue and loss of weight