What is the number of electrons in the last shell of an atom with a mass number of 20 and 4 neutrons

Me i need this asap during photosynthesis, the following reaction takes place: carbon dioxide + water + light energy → sugar + oxygen during cellular respiration, the following reaction takes place: sugar + oxygen → carbon dioxide + water + chemical energy given this information, how are photosynthesis and cellular respiration related? question 2 options: the products of photosynthesis are the reactants of cellular respiration. photosynthesis and cellular respiration both start with the same materials. photosynthesis and cellular respiration both produce the same materials. the same type of energy is found in both photosynthesis and cellular respiration.