Why am I so tired all day

In her notes, celeste wrote that the human body systems consist of molecules, cells, tissues, organs, and organ systems. what problem will celeste have on her body systems test when she studies this information? she forgot to list organism as a level. she should have written chemicals/molecules. this is not the correct sequence. these are not body systems.

Which of the following is an example of negative reinforcement? a.marty knocks over his mother's prize fern so she gives him a time out. b.gwen mows the lawn and her dad takes her out for ice cream. c.tara takes an aspirin, and her headache begins to go away. d. peter comes in late from his lunch and is fired from his job.

How do astronomers measure the amount of dark matter in the universe