Given a scientific question, generate a correct answer to it.

Input: Consider Input: Inside each lymph node is a honeycomb of connective tissue with spaces filled by what?

Output: white blood cells

Input: Consider Input: What process allows plants to convert light energy into sugars and energy for food?

Output: photosynthesis

Input: Consider Input: The negative logarithm of the hydroxide-ion concentration of a solution is called?
Output: the poh