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

• Carbon dating is used to estimate the age of fossils.
• Those that are less than 60,000 years old.
• It is composed of organic materials like wood or leather.

Explanation

• Cobalt-60 is used in radiotherapy to stop the growth of cancer cells.
  
• It emits gamma rays that target and destroy malignant cells in cancer treatment.

Explanation

Hydrocarbon compounds are typically derived from fossil fuels and consist of hydrogen and carbon atoms.

Examples include fuels like gasoline, natural gas, and propane, as well as waxes like candle wax and paraffin wax.

Explanation

Fertilizers are substances added to soil to provide essential nutrients for plant growth, making up for any deficiencies in the soil.

Fertilizers replenish nutrients in the soil that have been depleted by previous crops.

Types:

1. Natural fertilizers: Organic materials like manure and compost.
2. Synthetic fertilizers: Inorganic substances created for commercial use, such as ammonium nitrate or diammonium phosphate.