The pH scale measures the concentration of:  

The pH scale is:  

Which level of organization is larger than a community?  

In a water molecule, the oxygen atom is more electronegative than the hydrogen atoms, making the molecule:  

Which of these organisms is a eukaryote?  

_______ is the universal solvent.  

What is the best explanation for why theories change?  

Which sequence represents the hierarchy of biological organization from simplest to most complex?  

Which bond is the weakest?

____________ motor skills are used for things like holding a paintbrush.