When economists attempt to predict the spending patterns of U. S. households, they will typically view the as a primary determining factor that influences the individual consumption choices that each will make.

a. income level of each household

Explanation:

Household INCOME LEVEL goes far in determining how the household spends because to spend on goods and services, one needs funds.

People usually buy according to what they have or can afford and so using data on a household's income to infer what kind of goods and services they will buy or rather their spending pattern is only logical.

Such research will also show what happens when household income decreases or increases so using the income level of each household really is necessary.

answer; 5% is your answer; ///good luck

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.