In recent years, some firms have tried to deal with the plateau effect and also accommodate the different career motivations of mature scientists and engineers through a(n)

Dual-career ladder

Explanation:

Dual-career ladder can be defined as one of the career development plans, which is aimed in allowing upward mobility of employees without placing them into supervisory and managerial capacities. Any organization that's practicing dual career ladder usually leave technical employees with alternative opportunities that help in advancement of the organization.

the first question's answer is a.

i believe the answer is: returns on investments, no wages

people who belong in upper class society would most likely get there by obtaining multiple source of income, which a certain percentage of ownership for businesses. since most of them are job creator, they would most likely get their money from profit, not wages.