The one that is true about cells is Number two. The cell is the basic unit of a structure and function of life. The cells are what makes us living things. All living things are made up of cells.
The energy currency of the cells is ATP. This is used for example in photosynthesis where plant cells produce food and oxygen using carbon dioxide and glucose for the consumers. ATP is also used widely in all other cycles to produce different products.
Feedback loops are biological mechanisms whereby homeostasis is maintained. This occurs when the product or output of an event or reaction changes the organism's response to that reaction. Positive feedback occurs to increase the change or output: the result of a reaction is amplified to make it occur more quickly.
Explanation:
Methods to increase or reduce friction
Grease is added between the moving parts in machines, to reduce friction. Another method of reducing friction is by using bearings. When ball bearings are introduced between two surfaces friction is reduced because of the freely rotating metal balls.
