Living organisms are made up of energy and matter. How many elements have been found to occur in nature?

Iron reacts with oxygen to produce iron oxide (rust). this reaction is represented in an equation as 4fe + xo2 → 2fe2o3. identify the value of x that will balance the equation.

Most animal cell membranes have proteins that pump. ions out of the cell and potassium ions into this

Easy 6th grade work! 100 points! i need fast! compare the parts of a cell and the cell as a whole to another common nonliving system (i.e., a car, a city, describe the parts of a cell and their primary function.