Answer: oxygen
There is the s,p,d and f blocks, from groups 1-2 that is the s block, 13-18 that’s the p block, 3-12 is the d block and the f would be lanthanide(#57-71) and actinide (#89-103).
I’m not good at this but I’m guessing it’ll be the first one!
Photosynthesis turns sunlight, water and carbon dioxide into energy and oxygen. Clorophyll is also a result of this process. "Photosynthesis turns carbon dioxide and water into oxygen and carbohydrates, therefore a chemical change happens." (keep what you wrote there) "It is also an endothermic reaction because SOLAR energy needs to be inputted in order for photosynthesis to occur. The energy input is then stored in the bonds of the glucose that were formed in the plant as a result of photosynthesis."
Option B is correct,
With increase in concentration the density of reactants increases and the system becomes more crowded, the greater the reactants will come in contact with each other and collisions occur. If collision is in proper orientation and has optimum energy then its fruitful and yields product. So, the greater the number of reactants, the greater will be the chances of collision and the greater will be the production of products per unit time and hence, greater is the rate of reaction.