In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
A hummingbird’s brilliant throat colour is not caused by feather (1) ________, but rather by iridescence in the arrangement of the feathers. Light level, moisture, angle of viewing, wear and tear and other factors all (2) ______ just how bright and colourful the throat may appear.
Hummingbirds cannot walk or hop, though their feet can be used to (3) _____ sideways while they are perched. These birds have evolved smaller feet to be lighter for more (4) ______ flying. They will use their feet for itching and (5) _______, however.
Select the most appropriate option to fill in blank number 3.

In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
A hummingbird’s brilliant throat colour is not caused by feather (1) ________, but rather by iridescence in the arrangement of the feathers. Light level, moisture, angle of viewing, wear and tear and other factors all (2) ______ just how bright and colourful the throat may appear.
Hummingbirds cannot walk or hop, though their feet can be used to (3) _____ sideways while they are perched. These birds have evolved smaller feet to be lighter for more (4) ______ flying. They will use their feet for itching and (5) _______, however.
Select the most appropriate option to fill in blank number 3.