What type of bond joins the two hydrogen atoms and the single oxygen atom in a water molecule?

Select the correct order for the hierarchy of biological organization (from the the most complex to the least): 

Carlos says an atom has 3 electrons in the first shell and 4 electrons in the second shell. Someone should tell Carlos that …

Which of the following are signs that  a chemical reaction may have occured?  Select all that apply

Which of the following represents a hydrocarbon with  a double bond in it?

What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?

(Surveys and Questionnaires) Which should not be explained early when presenting results?

Carlos says an atom has 3 electrons in the first shell and 4 electrons in the second shell. Someone should tell Carlos that …

Match each substance to the correct symbol in a reaction equation at normal room conditions.

Select the correct order for the hierarchy of biological organization (from the the most complex to the least):