Answer:
Impairment of photosynthesis
Step-by-step explanation:
The major effect of oil spilage is that it impairs or hampers photosynthesis.
Photosynthesis is the process where green plants manufactures their own food in the presence of sunlight and water.
Water is denser than oil. Therefore, oil floats on the surface of water. Oil on water surface acts as a blanket to sheild plants away from receiving direct sunlight. Sunlight is very important during photosynthesis.
In the absence of sunlight, plants are unable to manufacture their food.
They are also unable to receive carbon dioxide from the environment.