Questions: Compounds with the same molecular formula, but different shape are called. There are only types of organic molecules essential for life. The gigantic organic biomolecules are called. Macromolecules are made by joining smaller molecules into chains called. The small molecules that serve as a building blocks are called. A reaction that links monomers together is called. A reverse reaction of breaking polymers back to monomers is called. Carbohydrates.

4. Compounds with the same molecular formula, but different shape are called isomers.
   Explanation: Isomers are molecules that have the same molecular formula but differ in the arrangement of atoms in space, resulting in different shapes and properties.

5. There are only four types of organic molecules essential for life.
   Explanation: The four types of organic molecules essential for life are carbohydrates, lipids, proteins, and nucleic acids.

6. The gigantic organic biomolecules are called macromolecules.
   Explanation: Macromolecules are large, complex molecules that are crucial for life, including proteins, nucleic acids, carbohydrates, and lipids.

In summary, isomers are compounds with the same molecular formula but different shapes, there are four types of organic molecules essential for life, and macromolecules are large organic biomolecules.