They are and cellular respiration. a) circulation b) digestion c) excretion d) photosynthesis

              The correct option is d (photosynthesis)
Reason:
              Photosynthesis and respiration falls in the category of bioenergetics and metabolism, because photosynthesis end product is glucose which is utilized in respiration to produce ATP.

This type of galaxy is an approximately ellipsoidal shape and a smooth, nearly featureless image. they are the largest single star systems, in the universe and are built by the collisions of many smaller galaxies.

Long term continuous groundwater monitoring, especially with warning systems and anthropic activity monitors