What are the answers to the following multiple-choice and fill-in-the-blank science questions?

Here are the answers to the questions from the image:

Multiple Choice Questions:

1. Plants make their own food in the presence of:

   • d. all of these
   • Photosynthesis requires sunlight, water, and carbon dioxide.

2. Rusting of iron can be prevented by:

   • a. galvanisation
   • Galvanisation coats iron with zinc, protecting it from rust.

3. Melting of butter is which kind of change:

   • a. physical
   • Melting is a change of state, not a change in chemical composition.

4. During exothermic chemical reactions heat is:

   • a. released
   • Exothermic reactions release energy, usually as heat.

5. Which gas is formed when Baking Soda and Vinegar reaction.

   • d. Carbon dioxide
   • The reaction between sodium bicarbonate (baking soda) and acetic acid (vinegar) produces carbon dioxide gas.

Fill in the blanks:

1. Chemical changes are usually irreversible in nature.

   • Chemical changes form new substances and are generally not easily reversed.

2. The process of crystallization involves cooling of a saturated solution.

   • Crystallization occurs when a solute comes out of a saturated solution as it cools.