During aerobic respiration, h2o is formed. where do the oxygen atoms in the h2o come from?

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

Food contains a sugar called ( ), which is broken down in a process called cellular ( ). this process uses ( ) to break down food molecules and provide energy for cells. fill in the parentheses