Explanation:
2. Cells are considered the basic units of life in part because they come in discrete and easily recognizable packages. That's because all cells are surrounded by a structure called the cell membrane — which, much like the walls of a house, serves as a clear boundary between the cell's internal and external environments.
3. The main significance of reproduction is to maintain continuity of species. It also helps in studying evolution as sexual reproduction results in variation among the species
4. All energy for life on Earth comes from the sun. After the energy leaves the sun it is used by plants on Earth where photosynthesis converts it to sugars. The plants store chemical energy that can be used by the plants, or converted into mechanical energy within an organism (e.g. an animal which eats the plant.)
5. A biological system is a complex network of biologically relevant entities. Biological organization spans several scales and are determined based different structures depending on what the system is. Examples of biological systems at the macro scale are populations of organisms
