How do we know the frequency of a wave when we can't see it?

In 1859, a french doctor noted that 67 of 68 oral cancer patients were:

An ostrich runs north in a straight line for 21 meters. She then turns around and runs 25 meters back toward her nest (south) on the same path. What is her displacement?

What is the term for a top predator that contributes to the maintenance of species diversity among its animal prey? A) keystone species B) keystone mutualist C) landscape species D) primary consumer E) tertiary consumer

Which sequence represents structures organized from least complex to most complex (1) nerve cell - nucleus - nervous system - brain (2) nucleus - nerve cell - brain - nervous system (3) brain - nervous system - nucleus - nerve cell (4) nervous

Rose has just given birth to her son, Isaac, and claims that David is the father. David says that he cannot be the father, because he and Rose have dark skin, but the child is albino with pale skin.

8. List at least 5 new discoveries about viruses.

The phospholipid molecule has two parts, the polar end and the bipolar end. True or False?

Giraffes use their extremely long necks to reach the lees high up on a case he had trees which other animals can not reach giving them a food source for which they have few competitors what can you conclude about natural selection from this

Which is a reason that many organisms that have existed on earth have left no fossils?

Are all organisms with similar physical characteristics related to one another? If not, why?