Photosynthesis produce 02 (oxygen)
If you are startled by the sound of a loud explosion, the sympathetic nervous system will become dominant. The sympathetic nervous system is responsible for regulating not only the functioning of the visceral organs (kidneys, digestive system and circulatory system) but also all the automatic functions of the organism, such as breathing, circulation, digestion and elimination.
Your answer would be B. The first one would be correct if the question was “how do we identify both bloodstains are from the victim”.
This might help! Hope it does here you go