what is the greatest limitation that scientists are dealing with as they try to figure out how to experiment with the Ebola vaccine?

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism

Which characteristics must an object possess in order to be considered alive?

Which promotes sustainability? o a. using more landfills o b. finding new sources of coal o c. increasing consumption o d. encouraging recycling programs