Assertion : Many visitors to the hills suffer from skin and respiratory allergy problem. Reason : Conifer trees produce a large quantity of wind-borne pollen grains.

Step-by-step solution

Some trees of hill like oak, ash, elm, hickory, pecan and mountain cedar produce allergic pollen grains which cause allergy to people. The signs and symptoms of pollen allergy are - sneezing - itching eyes, nose and throat - dark circles under the eyes caused by restricted blood flow near the sinuses - watering eyes - conjunctivities Conifer trees produce a large quantity of wind borne pollen grains because many pollen grains are destroyed in the process of pollination done by wind.