Idon't know any idea how to submit answer

Sometimes some questions don't have a submit button. This happened to me and I know that you just have to move onto another question. Then when you find one that has an answer button you type in you answer and press the answer button for points.

the answer is b.) hydrogen bonds between bases.

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.