Photosynthesis and Respiration — Question 15

Note the relationship between the first two words and suggest a suitable word/ phrase for the fourth place :

1. Photosynthesis : Day time :: Respiration : ...............
2. Photo : light :: Synthesis : ...............
3. Xylem : Water and minerals :: Phloem : ...............
4. Palisade cells : Barrel-shaped :: Guard cells : ...............
5. Photosynthesis : Chloroplast :: Respiration : ...............