The water on the Earth today has been sustaining life for millions of years.

Which idea originated with Charles Darwin?

You learned in the previous section that archaea have ribosomes, similar to eukaryotes. How does this statement support the theory that is presented in the article?

During which months do ocean surface elevations begin to rise along the equator, indicating the beginning of an el niño?

The final electron acceptor in cellular respiration is oxygen which reacts with hydrogen ions to form

Shelly is pessimistic about her future. Her disinterest for everything around her, together with worry and rumination, make it difficult for her to cope with even the most minor of daily events. These symptoms demonstrate which domain of depression?

What is it called when a person is in a state of deep unconsciousness from which he or she cannot be aroused?

To offset high levels of carbon dioxide which of the following is the most viable option? A. pump oxygen in using oxygen tanks B. include indoor plants C. take shorter or less breathes D. keep windows and doors closed

Steam power plants produce a large amount of extra steam. That steam is released as heat energy into the water surrounding the power plant.

Depending on the organism, the number of in a cell may change.

Complex organisms develop specialized tissues as a direct result of which of the following processes?