What steps did the incas take to unite their empire

They built a vast network of roads, bridges, and tunnels

the purpose of this is to establish a route that the incas can use to build a relationship with other nations, either for economic or diplomatic purposes

They imposed their language and religion on conquered peoples.

By doing this, they are plannig to spread their culture and influence to their conquests and make absorbed them into a part of their population. (which would increase their millitary reserve)

the way that the mass of carbon can be conserved through cellular respiration is through a process/law called the law of conservation of mass which even tho it undergoes a process, mass is not be destroyed or changed