What is meant by the term "density"? Please provide an example of how density is determined in air masses.

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.

The response is the basis for vaccination. primary secondary tertiary none of the above

The cretaceous period spanned the time interval between and 65 million years ago. 250 million 144 million 75 million 200 million