Why are the lymphatic system and the circulatory system called “closed systems?” (any bots or links will be reported)

What can be said about farmers in highly developed countries? a) they have little or no negative impact on the environment. b) they practice subsistence agriculture. c) they are able to incorporate polyculture into their farming practices. d) they utilize organic farming techniques on a regular basis. e) they rely on large amounts of energy from fossil fuels.

Climate warming trends allow plant and insect species to inhabit larger ranges. select the best answer from the choices provided

Which characteristics are typical of a human population in the postindustrial stage?