I believe this is a double replacement. As you can see none of the chemical symbols are missing, there just "replaced".
Answer:
1. Many different hypotheses will be tested.
Explanation:
Scientists test every hypothesis they make for their investigation, before moving onto bigger conclusions.
Answer:
gyhgguuuyiiuyhjuhjiokjhgyhjiuh
Explanation:
lol
The best answer is the first option. A bike rusting is an example of a chemical change since rusting is a chemical reaction. New substances are formed from this reaction. On the other hand, other choices given are just physical changes because only the shape or the physical form of the substances are being changed.