Which type of organism is made of specialized cells that work closely together to keep an organism alive? A. none of these B. multi-celled C. single-celled D. specialized

B

Explanation:

Multicellular organisms have many different specialised cells each of which perform a specific function.

The cells are grouped based on their functions, into tissues, organs and organ systems.

C is incorrect because the question asks about organism made of specialised cells. It can't be single-celled.