How long does it take for sperm to fertilize an egg?

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

Which component in a graph indicates an independent factor? a. y-axis b. x-axis c. scale

Cladistics is a way of classifying organisms by examining the characteristics of their ancestors and descendants and depicting the relationships in a cladogram. which of the following best describes a challenge in classifying organisms this way? a. there are millions of species on earth, and a cladogram is not a practical means for classifying all of them. b. it is impossible to tell which organisms are most closely related to each other using a cladogram. c. cladograms are detail-oriented and do not provide a useful understanding of evolutionary relationships. d. there is a limited number of ways to organize the information, so most cladograms end up looking very similar.