Question

why some leaves are red in colour

Answer 1

Here is your answer friend,
Some leaves are green in colour because due to the presence of other red coloured pigments but still these plants can perform photosynthesis.These plants also contain chlorophyll pigment.
Hope it's useful and helpful!!!
@#shakti37

Answer 2

PLANTS have other pigments like carotenoids and anthocyanins where carotenoids are responsible for yellow to orange colour in leaves and anthocyanins for red to purple , one pigment is usually dominated in the plant and probably the plant with more anthocyanins has red leaves but then also they have chlorophyll present in them .
Hope it helps