Explain why capillaries form dense networks in tissues with a high metabolic rate

  A high metabolic rate means that the cells in the tissue will needs a high rate of gas exchange as the cells will be producing a high amount of CO2 during production of energy.  The dense network of capillaries ensure that the cells are adequately provided with oxygen.                                                                                                                                                                                           

i believe the correct answer from the choices listed above is the first option. the scientists need to look at the   validity of data, claims, hypotheses, and observations before  developing an argument. they base their arguments on facts that are present and they make sure they have proofs. 

explanation:

b. the carbon cycle ensures living things have a source of hydrogen