What factors facilitate erosion by wind? a. heat, low water table and low humidity
b. ocean currents, La Niña and El Niño
c. drought, plant die-off and wind
d. increased solar flares, close solar orbits and sunspots

The diagram shows a fossil of an ancient whale skull and a skull of a present-day whale. the ancient whale is extinct and is believed to be an ancestor of the present-day whale. what do these skulls most likely show that supports darwin’s theory of evolution? all populations can adapt and survive. only some organisms have a common ancestor. populations change slowly over time. populations rapidly become extinct.

When fossil fuels are burned, carbon dioxide is released. how does this gas impact the environment?

Who discovered tuberculosis bacteria?