Well because animals can seek shelter and plants can't move at all.
If referring to photosynthesis, carbon dioxide is brought into the cholorplast of the plant cell, it is then fixed to RUBP, it will go through a series of Redox reactions and become G3P. RUBP is then recycled and is used to fix more carbon dioxide. You need two G3P molecules to become glucose.
A nucleic Acid is a long repeating chain of nucleotides