You must know that the main site of photosynthesis, is Chloroplast which is present in the leaf. Chloroplast contains a green pigment (appears green colour) called chlorophyll.

Remember, a light or objects looks black, when an object absorbs all the seven colours and reflects none. That time it looks like black in colour.

Bile is dark green or a yellowish-brown fluid which is produced by the liver and comes to the small intestine through hepato-pancreatic duct.

Solution of pH can be made, when Sodium hydroxide (NaOH) that dissolves in water to form a solution. Which has pH as greater than 7. Because it is an alkali.