When Ruby practice piano she gets a sticker, and when she does a chore she gets 2 stickers. When she has 20 stickers her
parents will buy her a pizza as reward. This system is called?

Should the u.s limit the number of terms a lawmaker can serve in congress

Federalism began to spread super soon after

Which statement below accurately describes the carrying capacity of any ecosystem? a. it is not affected by any abiotic or biotic resources. b. it does not affect the species of an ecosystem. c. it is completely dependent upon the food supply. d. it is affected by both abiotic and biotic resources