Choose all the answers that apply. What does the cardiovascular system do?

transports oxygen and carbon dioxide for the respiratory system
carries nutrients for the digestive system
works with the immune system to fight infection
carries hormones for the endocrine system
sends nerve impulses to the brain and spinal cord

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?