What is meant by allele frequency? a. the rate at which alleles occur b. the number of species that have the same trait c. the time it takes alleles to changes d. the number of generations in one population

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

The influenza virus cause the flu, but not other diseases. why?

Which phrase is the best summary of the model shown? a. the transfer of the sun's energy through trophic levels b. a series of aerobic and anaerobic reactions c. a transformation of light energy into chemical energy d. the breakdown of food molecules