What was one of the ways that people of ancient times classified plants and animals?

What is the mrna strand that would be copied from this dna strand

The skeletal system performs a variety of functions that are crucial to maintaining life processes. what function is performed in the bone marrow, but not in the ossified bones of the skeleton? a oxygen transportation c mineral storage b. muscle attachment d red blood cell production

Which state of matter has the following physical properties: ~ takes the shape of the container it is in ~ takes the volume of the container it is in ~ low density. answer is gas