Johnny is tapping his foot softly on the ground. When Melanie is standing up, she can barely hear his foot tapping. But if she puts her ear on the floor, the sound is very loud. Why is this?
A.
Sound waves travel faster through air than through solids.
B.
Sound waves reflect off of light particles.
C.
Sound waves can travel farther through solids.
D.
Sound waves are blocked by other sound waves.

Which of these is a major trend in land plant evolution? a) the trend toward smaller size b) the trend toward a gametophyte-dominated life cycle c) the trend toward a sporophyte-dominated life cycle d) the trend toward larger gametophytes

New york city has 2,181 inhabitants per square mile. the state of alaska has 1.03 inhabitants per square mile. ecologists would say alaska has a low exponential growth population density birth rate carrying capacity

Choose one animal (cheetas) and research on the internet what has contributed to this animal becoming "endangered" or "threatened." what animal you have chosen? how long has the animal been endangered or threatened? what has contributed to this animal’s endangered or threatened status? why is it important to save this animal from extinction? after researching and gathering facts, write a 350-word letter from the point of view of an animal rights' activist. be sure to include at least five facts that you learned from your research.