Muscle cells need large amounts of energy to keep the body moving. Which organelle would you expect them to hold in very high concentration?

1. The energy currency of the cell is ATP, and mitochondria are the organelles that make it. 2. Cells with heavy energy demands stock up on the ATP makers. 3. Muscle cells have a very high concentration of mitochondria for exactly this reason. 4. Chloroplasts capture light in plants, and animal cells have none, so that option fails twice over. 5. Lysosomes digest waste; more digestion does not supply the energy that movement demands. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 4 "Cell Structure", section 4.3 Eukaryotic Cells_