Which best describes two ways in which hydrogen is involved in photosynthesis? 1 - Hydrogen is stored in leaves of plants. 2 - Hydrogen combines with carbon dioxide to make glucose. 1 - Hydrogen is stored in leaves of plants. 2 - Hydrogen combines with oxygen to make water. 1 - Hydrogen enters plants as a component of water. 2 - Hydrogen combines with carbon dioxide to make glucose. 1 - Hydrogen enters plants as a component of water. 2 - Hydrogen combines with oxygen to make carbon dioxide.