Which of the following statements is true about prairie dogs? a. prairie dogs have a specific call to indicate the intelligence of the predator. b. prairie dogs vary their call depending on the characteristics of a predator. c. prairie dogs vary their call only when their community is out of danger. d. prairie dogs have one basic call that indicates the presence of predators.

What is the tychonic system? a. a model of the solar system in which all the planets (including earth) orbit the sun b. a model of the solar system in which the planets, moon, and sun orbit earth c. a model of the solar system where the planets orbit the sun, and this system orbits earth d. a model where all the planets and earth are fixed in space and only the sun and moon move e. a model that expands the system to a vast number of galaxies and star systems