What is the average density of the earths crust

Which of these is not a function of some membrane proteins ? a.allowing polar molecules to enter the cell b.recognizing other types of cells c.receiving messeges from other cells b.carrying messages to oher cells

Will someone me with this.. specialized cells which perform a particular function form: tissues organs or organism

Students commonly confuse saccharomyces cerevisiae and staphylococcus aureus when viewed on a microscope slide how could you microscopically differentiate