Glutamine and Glycine are not basic amino acids. Only Arginine and Histidine are basic amino acids. Histidine is weakly charged under physiological ph. Hence, Arginine is the most basic amino acid. 

Polycyclic aromatic hydrocarbons are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage or other organic substances, such as tobacco and charbroiled meat.
They are the carcinogenic or cancer-causing substance in the tobacco smoke.
Therefore, the correct answer is option B.

Cocaine are stimulants that is they elevate mood, increase feelings of well-being and increase energy and alertness.
Opium  and morphine are powerful pain-killers. They produce a quick, intense feeling of pleasure followed by a sense of well-being and calm.
Barbiturates are depressants that slow down the normal brain function.
Thus, the correct answer is 'Barbiturates cause relaxation and temporary euphoria'.

Smoking is associated with significant morbidity and mortality. Smoking still remains one of the leading causes of preventable death. Smoking has the dubious distinction of affecting all the systems from head to foot. Cigarette smoking causes many types of cancer. It also increases the risk of cardiovascular diseases. Exposure to tobacco smoke during pregnancy can lead to delivery complications and increase the risk of health problems in the newborn. Quitting smoking significantly reduces the health risks caused by exposure to tobacco smoke. 

Tobacco (Nicotiana tabacum) belongs to family Solanaceae, is a silent long term killer can be consumed in a variety of ways like smoking, chewing, sniffing etc. Nicotine is a highly poisonous substance found in tobacco that increases pulse rate and blood pressure. It also increases stomach acidity, which is accompanied by a lack of appetite. Over time, tobacco users can look forward to such serious risks as narrowing or hardening of the arteries, respiratory infections, emphysema, stomach ulcers, chronic cough, and cancer of the mouth, throat, and lungs.

Emphysema is a respiratory disorder which occurs due to the inflation or abnormal distension of the bronchioles or alveolar sacs resulting in the loss of their elasticity. Cigarette smoking and chronic bronchitis are the causes of this disease.

Hemoglobin has four chains: two alpha chains and two beta chains with heme and iron part along with oxygen. There are some hydrophobic substances (water-hating) present on the surface of proteins. These hydrophobic residues forms cluster and pocket-like structure on the surface of beta chains. These pockets are responsible for diseases like sickle cell anemia also in the beta chain the position of glutamic acid at sixth place in the chain is replaced by valine leading to the shape of red blood cells to be sickle-like due to loss of oxygen.

Emphysema is. a condition of short breath due to breakdown of alveolar wall and'reduction of respiratory area due to smoking.

• Myeloma, also known as multiple myeloma, is a blood cancer arising from plasma cells. 
• Plasma cells are a type of white blood cell made in the bone marrow. Bone marrow is the ‘spongy’ material found in the centre of the larger bones in the body and is where all blood cells are made. 
• Myeloma develops when DNA is damaged during the development of a plasma cell. 
• This abnormal cell then starts to multiply and spread within the bone marrow.
• Hence, Cells obtained from cancerous tumours are known as Myeloma.
•  So, the correct answer is 'myeloma'.

Cancer is a group of disease, that involves abnormal cell growth (abnormal cell division), with the potential to invade or spread to other parts of the body. They compete with normal cells for nutrients. Contact inhibition is a growth mechanism, which functions to keep cells growing into a layer one cell thick or monolayer. The cancer cells do not show contact inhibition and they grow uncontrollably.
Thus, the correct answer is option (D), 'They show contact inhibition'.

• HeLa cells are the cell type in immortal cell lines used in scientific research. It is the oldest and most commonly used human cell line.
• The line was derived from cervical cancer cells taken on February 8, 1951, from Henrietta Lacks, a patient who died of her cancer on October 4, 1951.  These cells are grown in a laboratory and are used for conducting many experiments.

Cancer is a group of diseases involving the abnormal cell growth where there is invasion of the local tissue and there is a potential to invade or spread to other body parts .
Therefore, the correct answer is option D.

During tumorigenesis, cancerous cells undergo rapid cell division and compete with normal cells for nutrients.
Cancer cells spread to other parts of the body, a process called metastastize i.e., are not confined in area  of formation.
Cancer is the result of cells that uncontrollably grow and do not die.
So, statements A, B and C are correct.
Normal cells when grown in culture, will become growth inhibited, when they encounter another cell. This is contact inhibition and Cancer cells show no contact inhibition as they do not stop dividing and keep growing.
Thus, the correct answer is option (D), 'They show contact inhibition'.

Metastasis is the movement of spreading of cancer cells from one organ or tissue to another. Cancer cells usually spread through the blood or the lymph system. It is mainly caused due to the mutagens which cause a sudden heritable change in the DNA content which leads to fatal abnormalities.
So, the correct answer is option B.

Genes are found in the DNA of every cell of the human body. The functions of the cell, its growth pattern, divisions and life are all determined and control by the genes. Cancers in the human body are the result of mutations or changes in one or more genes in a cell leading to an abnormal protein or no protein at all. An abnormal protein in the cells causes them  to multiply uncontrollably and become cancerous. Any alteration in the tumour suppressor gene may result in cancer. 

Cancer cells are cells that divide rapidly, forming solid tumours or flooding the blood with abnormal cells. Malignant cancerous cells spread from their initial site to other organs or tissues resulting in metastasis. Cancer cells undergo invasion of local tissue i.e., direct extension and penetration by cancer cells into neighbouring tissues. Hence, cancer cells are characterised by uncontrolled growth, spreading to other body part and invasion of local tissue.

• A gene is the basic physical and functional unit of heredity. Genes are made up of DNA and DNA is present inside the nucleus.
• Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death. As a mass of cancerous cells grows, it can develop into a tumour.
• Hence Transformation of a normal cell to cancer cell may start with changes in  Nucleus.
  
• So, the correct answer is 'Nucleus'.

The difference between normal tissues and cancer tissues is the rate of metabolism.  In normal cells, hundreds of genes intricately control the process of cell division. Normal growth requires a balance between the activity of those genes that promote cell proliferation and those that suppress it. However, in the case of cancer cells, they involve abnormal growth. Cells become cancerous after mutations accumulate in the various genes that control cell proliferation. Hence proliferation of cancer cell is not limited because of differing surface proteins and aberrant chromosomal complements. Thus, the correct answer is option D.