Question

1. when elements combine to make a compound the new substance has properties from the original they may have a new

practice: element or compound?

Explanation:

The question is about elements combining to form compounds and the properties of the compound. In chemistry (a subfield of Natural Science), when elements combine to form a compound, the compound has properties different from the original elements. So the blanks should be filled with "different from the original" and "set of properties" (or similar relevant terms about chemical properties of compounds).

Answer:

When elements combine to make a compound the new substance has properties \underline{different} from the original. They may have a new \underline{set of properties} (or other appropriate terms related to chemical properties of compounds, e.g., "chemical properties")