The correct answer is (a) driving.
The pressence of undesirable substances in air is called as air pollution. There are many human activities that contribute to air pollution. The biggest contributor is driving. The pollutants that comes out of the car are carbon dioxide, carbon monoxide. They also release hydrocarbon and nitrogen oxides which when combines in sunlight becomes ozone. Air pollutants emitted by cars and other automobiles increases the level of harmful gases which to severe health problems such as heart disease, asthma, irritation in eyes.
Answer: if they help you break down food
Explanation:
Mutualism is a biological relationship between TWO or more organisms of different species (inter-specie) in which one or more benefits.
A good example is bacteria in the human intestine that helps to break down cellulose contained in food, thus benefitting humans.
Salt marshes are primarily influenced by the tidal flow.
