A population of finches lives on an island with two food sources, hard nuts and small seeds. Big beaks can crack the nuts but not reach seeds while small beaks can reach the seed but not access the nuts.

A population of salamanders contains two skin colour phenotypes; red and blue. All are capable of interbreeding, with red skin being preferred by most females, but blue skin being preferred by females with a particular mutation affecting their eyes. Over time, two distinct species of salamander are found within this location, one red, one blue.

You have discovered two populations of birds living within a rainforest. Through observation, you have noted the two populations have an identical body plan and feather patterns.

Suppose you have a population of mice, 1/3 with darker fur, 1/3 with medium fur and 1/3 with lighter fur. These mice live on light coloured soil, and predation results in a selection for the lighter phenotype.

 In the 1959 classic, Attack of the Giant Leeches, our plucky heroes must escape the giant annelids the size of humans. Luckily for us, giant leeches can likely not exist due to?

 Imagine a terrestrial organism roughly 2cm in length with an exoskeleton, it would most likely have:

 Which of the following circulatory systems results in the mixing of deoxygenated and oxygenated blood in the systemic circulation?

A mad scientist in a movie has breed 50m tall insects, however in reality it would not be particularly effective at crushing the protagonist. Which of the following reasons would LEAST contribute to the inability of this creature to exist.

An organism has a hardened exoskeleton covering the entirety of its body and 6 jointed legs. Which of the following would you also expect to find?

 The main components of mammalian bone are?