Choose the correct way to complete the sentences to explain technological developments in the twentieth century. and are technological developments of the twentieth century.

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

In which of these cases are the two wave points considered to be in phase with each other?

Which of these is not an example of chemical weathering? a. iron-rich mineral rusting b. feldspar turning into clay c. limestone reacting with acid d. granite breaking up into sand