Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: To harness water power, a stream must be dammed. Narrow valleys are the best for dams. While sitting in the reservoir behind the dam, the water has potential energy. Water is allowed to flow downhill into a large turbine. While flowing downhill, the water has kinetic energy. Kinetic energy makes the turbine spin. The turbine is connected to a generator, which makes electricity. Answer: kinetic energy
[A]: Water is allowed to flow downhill into a large turbine to harness power. what helps the turbine spin?

[Q]: Passage: In addition to having a plasma membrane, cytoplasm, a nucleus and ribosomes, eukaryotic cells also contain membrane-bound organelles . Each organelle in a eukaryote has a distinct function. Because of their complex level of organization, eukaryotic cells can carry out many more functions than prokaryotic cells. The main differences between prokaryotic and eukaryotic cells are shown in Figure below and listed in Table below . Keep in mind that some eukaryotic cells may have characteristics or features that other eukaryotic cells lack, such as the cell wall. Answer: eukaryotic cells
[A]: Which type of cell can carry out more functions, eukaryotic cells or prokaryotic cells?

[Q]: Passage: All matter is made of tiny particles. Protons, neutrons, and electrons form atoms that bond together to create molecules. Atoms are the smallest units that have the properties of an element. Molecules are the smallest units of a compound. Chemical bonds hold molecules together. Molecules form the different types of minerals. The silicates make up most of Earth's crust. Minerals come together to create the three major rock types. They are igneous, sedimentary, and metamorphic. Igneous rocks form from cooled magma. Sedimentary rocks form from compacted or cemented sediments. Metamorphic rocks are those that have been altered by heat and pressure. These three rock types are the material part of the rock cycle. They are connected by different processes. Different processes convert any type of rock into any other type of rock. These processes are weathering and erosion, crystallization, and burial and pressure, among others. Each rock contains a story of how it formed. For most rocks it is possible to know what it formed from. Answer: atoms
[A]:
The smallest units of matter that retain the unique properties of an element are known as what?