Explanation

• Human insulin is inserted into bacteria, specifically E. coli, for the commercial preparation of insulin.
• This is done through genetic engineering, where the human insulin gene is cloned into a plasmid and then transformed into E. coli cells.
• The bacteria then produce human insulin, which can be harvested and used as a medication for diabetes.

Explanation

The correct answer is: No change in composition

• A chemical change involves a transformation of one or more substances into new substances, which means a change in composition.

The signs of chemical change:

• Release of gas
• Change in color
• Change in temperature
• Change in smell
• Production of a new material

Explanation

The atomic mass (A) is the sum of protons and neutrons in the nucleus. In this case:

• Protons (Z) = 11
• Neutrons (N) = 12
• Atomic Mass (A) = Z + N = 11 + 12 = 23

Explanation

• When light travels in a straight line and strikes the surface of another medium, it reflects off the surface and changes direction.
• This is known as reflection.

Explanation

• In a saturated solution, the solvent has dissolved the maximum amount of solute possible under the given conditions.
• It leading to equilibrium between the dissolved and undissolved solute.

Explanation

• Lemon juice, which is primarily liquid, dissolves in water, another liquid, creating a liquid-liquid solution.
• Where both solute (lemon juice) and solvent (water) are in liquid form.

Explanation

• The cell membrane, also known as the plasma membrane.
• It is a thin layer of lipid and protein molecules that surrounds the cell and regulates the movement of substances in and out.
• It is partially permeable, allowing certain substances to pass through while keeping others out.

Explanation

The particles in a gas have the following characteristics:

• They move randomly, with no fixed pattern or direction
• They have unlimited space to move, as there are no boundaries or restrictions
• They move freely in any direction, without any obstacles or barriers
• They can travel long distances, as there are no constraints on their movement

Explanation

• Plastic bottles are not biodegradable.
• As they are made from synthetic materials that are resistant to decomposition.
• It can take hundreds or thousands of years to break down.

Explanation

• Solid wastes that are not easily decomposed by decomposers, such as bacteria, fungi, and other microorganisms, are called non-biodegradable wastes.
• These wastes are resistant to decomposition and can take hundreds or even thousands of years to break down.

Examples of non-biodegradable wastes include:

• Plastics
• Glass
• Metals
• Synthetic materials
• Chemicals
• Pesticides