What two organelles are thought to be a result of endosymbiosis

Which term describes the difference in the concentrations of a substance across a cell's membrane?

A biologist who studies the transmission of genes from one generation to the next is called

What are the four tenets of natural selection?

A bulls eye rash is associated with infections of which of the following? A. Yersinia pestisB. Epstein-Barr virusC. Borrelia burgdorferiD. Francisella tularensisE. dengue virus

What influences the path that surface currents take? A. salinity and Earth's rotation B. wind forces and Earth's rotation C. differences in density and temperature D. wind forces and salinity

What is the volume of a 50mg object with a density of 20g/ml?

The water changes from cold to warm at the North Pacific Buoy Station. Where does the cold water likely come from?

An individual with the genotype BBTt could produce the gametes O A. BB and Tt only B. BB, Tt, BT and Bt only O C. BT and Bt only O D. B, T and t only

Which two body systems must directly interact for vertebrate organisms to exchange gases?

After strenuous exercise sore muscles can occur because