What is the difference between endothermic reactions and exothermic reactions for biology? also, what are the reactants of photosynthesis?

In tomato plants, mendel found that the allele for smooth seeds (s) is dominant, while the allele for wrinkled seeds (s) is recessive. which of these punnett squares shows crosses between two plants heterozygous for smooth seeds? i need this to be answered as soon as ! sry the picture is bad quality