Natural populations fluctuate through time. One of the forces causing variation in population size is variation in the physical environment, which can have both direct and indirect effects on populations. Variation in population size linked to environmental factors (aside from those that occur daily or seasonally) is likely to:

A) be predictable and constant.
B) be density-dependent.
C) affect the biotic potential exponentially.
D) be irregular, perhaps even random.
E) track the logistic growth model.

In which of the following ways is the function of the surface of a microsphere similar to the function of an actual cell membrane? a.both make it possible for the conditions in the interior to be different from the conditions outside. b.both provide a barrier that keeps water from flowing across it so the interior remains dry. c.both separate the rna that forms in the interior from any rna that might form in the environment. d.both can actively move molecules into the interior or out into the surrounding environment.

During binary fission, what events must occur before the cell splits into two new cells?

Fredrick griffith made a scientific discovery in 1928