4. What specific tool is used to way the cost of benefit versus cleanup in the environment?

 Marginal analysis

Explanation:

Marginal analysis is used to evaluate the marginal benefits and marginal costs of reducing pollution.

As the complexity of environmental protection grows, inexpensive and simple ways of mitigating emissions start to decrease, and more costly approaches need to be used and the marginal cost is increasing. Often, marginal benefits are reduced as environmental security increases.  

As the amount of protection for the environment rises to, the marginal costs outweigh the marginal benefits. Society is not allocating resources effectively at this stage of environmental security, since so many resources are giving up to reduce emissions.

As the scope of the environmental regulation grows, additional environmental spending will likely result in increased marginal costs.

Hence, marginal analysis is a specific tool used to way the cost of benefit versus cleanup in the environment.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.