Water vapor can make up as much as 90% of the greenhouse gases by volume in earth's atmosphere. however, water vapor is rarely identified as a major agent of climate change. what best describes the role water vapor plays in the greenhouse effect?

As it can hold CO2 and CFC, it's the major one for the greenhouse effect.

Explanation:

Water, which evaporated from the sea and other sources, directly goes upward and stays in the form of the cloud. This cloud can change the environmental situation of any place. Such as, it can make rainfall, snowfall, etc. Along with this, it holds CO2 and CFC gas. If the cloud of any place is denser, it contains more CO2 and CFC gas, which can increase temperature and cause the greenhouse effect. For this reason, this is called the major one for the greenhouse effect.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.