The circulatory system of a whale is considered an organ system because it is composed of different a. cells. b. tissues. c. organs. d. molecules. e. heart.

organs

Explanation:the body of multicellular organisms are organised into levels of organization.these levels increases in complexity.

The macromolecules makes up the organelles . organelles in turn makes up the cell.A group of similar cells at a certain location makes up an organ.for example the heart consists of a number of cells.

A group of organs which work together to achieve a specific function in the body , makes up the organs system.

For example the circulatory system of a while is made up of different connected organs - heart, blood vessels,to perform the function of transporting blood around it's body.this makes it an organ system.

allowed for the prediction of the properties of missing elements.

your answer would be a, maximum exploitation of resources.