What do you mean by photosynthesis?

Deer cave cannot support photosynthesis is as not enough sunlight is present. in spite of this, it still has a complex food chain. what is the energy foundation of this food chain?

In the presence of oxygen, glycolysis is followed a. the krebs cycle b. lactic acid fermentation c. alcoholic fermentation d. photosynthesis

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?