Question

which of the following is the primary challenge associated with recycling glass?

lack of recycling centers
excessive weight in landfills
lack of recycling knowledge
high transportation costs

Explanation:

Glass is heavy, and transporting it over long distances for recycling can be costly. Lack of recycling centers is less common as many areas have them. Excessive weight in landfills is a result of not recycling, not a challenge to recycling. Lack of recycling knowledge is not the primary issue as recycling glass is relatively straightforward. High transportation costs due to glass's weight are the main hurdle.

Answer:

high transportation costs