Answer: B

Explanation:

Radioactive pollution is a form of nuclear pollution that occurs when radioactive materials are present in the environment. It can be caused by natural or man-made radioactivity. Radioactive pollution is dangerous because it emits ionizing radiation that can damage tissues and DNA. The radioactive materials emit hazardous ionizing radiation, such as beta or alpha particles, gamma rays, or neutrons into the environment. Hence, statement 1 is incorrect.

Some sources of radioactive pollution include: mining and testing of radioactive materials, nuclear power stations, nuclear weapons, and medical diagnostics and treatment procedures. Radioactive pollution differs from conventional pollution in that it cannot be detoxified or broken down into harmless substances. Instead, radioactive materials must be isolated from the environment until their radiation level has decreased to a safe level. Hence, statement 2 is correct.

Answer: B

Explanation:

The extent to which computers have entered into various facets of life is one of the reasons that has increased the vulnerability of the technology to mischief. Everything from banks to schools to various government and business organisations are utterly dependent on computers. If by any chance a system or a network is sabotaged, the damage is enormous. Apart from threats like natural disasters, the most difficult threat to computers systems and users comes from viruses. Hence, statement 1 is incorrect.

Viruses are computer programmes usually written by a programmer, that attaches itself to other programmes and alters them or destroys stored data. Hence, statement 2 is correct.

Antivirus software may be installed; this can detect and eliminate known viruses when the computer attempts to download or run the executable (which may be distributed as an email attachment, or on USB flash drives). Some antivirus software blocks known malicious web sites that attempt to install malware. An antivirus software application uses two common methods to detect viruses. One (also the most common method of virus detection) is using a list of virus signature definitions. Hence, statement 3 is incorrect.

Answer: A

Explanation:

The immune system is a complex network of organs, tissues, cells and molecules that work together to protect the body from pathogens (such as bacteria, viruses and fungi), as well as other foreign substances. Major components of the immune system include the thymus, bone marrow, lymph nodes, spleen, tonsils, and specialized immune cells. Hence, statement 1 is correct.

T cells and B cells are crucial components of the immune system and are responsible for recognizing and targeting specific pathogens. B cells produce antibodies which are proteins that can bind to specific pathogens and help in their neutralization or elimination. T cells, on the other hand, have different roles including the recognition and destruction of infected cells or abnormal cells within the body. Hence, statement 2 is correct.

Answer: A

Explanation:

Vitamins are indeed organic compounds that are required in small quantities for various physiological functions in the body. These compounds are essential for the proper functioning of processes such as metabolism, growth, development, immune function and maintaining overall health. Vitamins are classified into two categories: fat-soluble vitamins (such as vitamins A, D, E and K) and water-soluble vitamins (such as vitamin C and the B-complex vitamins). Hence, statement 1 is correct.

Minerals are inorganic substances that are indeed required by the body for proper functioning but they are needed in relatively smaller quantities compared to macronutrients such as carbohydrates, proteins and fats. Minerals play various essential roles in the body including maintaining the balance of fluids, contributing to nerve and muscle function, participating in metabolic processes and forming structural components of bones and teeth. Examples of minerals include calcium, iron, potassium and zinc. Hence, statement 2 is incorrect.

Answer: A

Explanation:

Apoenzyme: It refers to the protein component of an enzyme which is usually inactive without its non-protein component called the cofactor.

Cofactor: It refers to the non-protein component of an enzyme which is required for its catalytic activity. Cofactors can be organic molecules called coenzymes or inorganic ions such as metal ions.

Holoenzyme: It refers to the complete, active enzyme which includes both the protein component (apoenzyme) and the non-protein component (cofactor).

Coenzyme: It refers specifically to a type of cofactor that is an organic molecule. Coenzymes are often derived from vitamins and are required for the activity of some enzymes.

Hence, option (a) is the correct answer.