Q. Which of the following are true concerning living things? Check all that apply. (2 pts) 1: They contain a vital force absent in nonliving things.
2: They are composed of molecules that contain carbon-carbon bonds.
3: They undergo chemical reactions to use energy they acquire from the environment.
4: They do not require catalysts to sustain their living state.

Explanation:

2 They are composed of molecules that contain carbon-carbon bonds.  

3. They undergo chemical reactions to use energy they acquire from the environment.  

Living things includes all the organisms that display features which make them distinct from non-living organisms. The living organisms  have an organized structure, they are composed of cells, they require energy to survive or sustain existence, they are able to reproduce and they exhibit ability to grow.

They are composed of molecules that contain carbon-carbon bonds: Carbon is the main component present in all living things. They make up the organic biomass of these living organisms.

They undergo chemical reactions to use energy they acquire from the environment: The plants traps sunlight energy and converts it into food and lastly into chemical energy in the form of ATP. This ATP is used as a energy reservoir for metabolic processes occurring in the plants. Therefore, energy is generated after chemical reactions.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

a = executive branch; b = judicial branch