Which is the most likely cause of the observed variation?
differences in the climate among the islands
competition among individuals for available food sources
competition among individuals for desirable mates
differences in egg size among the populations

Iron reacts with oxygen to produce iron oxide (rust). this reaction is represented in an equation as 4fe + xo2 → 2fe2o3. identify the value of x that will balance the equation.

Atypical human cell is approximately 12.00 μm in diameter and enclosed by a membrane that is 5.000 nm thick. (a) what is the volume of the cell including the membrane? (b) what is the volume of the cell membrane? (c) what percent of the total volume does its membrane occupy? to simplify the calculations, model the cell as a sphere. enter your answers using four significant figures.

Consider darwin's first writings on the theory of natural selection. an important point of darwin's essay on the principle of population, written in 1798, was a peer's observation that in nature plants and animals produce far more offspring than can survive, this observation can be attributed to a) charles lyell. b) thomas malthus. c) jean-baptiste lamarck. d) johann friedrich meckel.