Dna is made of two chains of nucleotides. which type of bonds hold the chains together?

Are the earth's ocean floor and continents the same age geologically? why or why not?

Nerve cells are specialized to respond to stimulitrue or false?

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