Fish and Insect Gas Exchange

As their main gas exchange organ, fish use [blank_start]gills[blank_end]. Their structure consists of [blank_start]an arch[blank_end] from which [blank_start]filaments[blank_end] project. Each filament contains many [blank_start]lamellae[blank_end], through which capillaries run. This is the site at which gas exchange takes place. The blood flows through the capillaries in the [blank_start]opposite[blank_end] direction as/to the water that flows through the gills, creating a [blank_start]countercurrent[blank_end] exchange. This ensures there is a favourable gradient in [blank_start]water potential[blank_end] between the water and the blood.

The structure that covers the gills of a fish is called the [blank_start]operculum[blank_end].

Label the diagram of the insect's gas exchange system, labelling answers in plural form.

Which of the following correctly explain how gas moves dynamically throughout the insect's gas exchange system? Check all that apply.

Spiracles constantly expose the inside of an insect's gas exchange system to the outside world.

Which of the following are adaptations of spiracles to gas exchange?