How do mammals keep their gas exchange surface moist?

• By using air sacs to store extra air

• By having mucus in the trachea

• By opening and closing spiracles

• By having water at the ends of their tracheoles

Answer explanation

Mammals keep their gas exchange surface moist by having mucus in the trachea, which helps in maintaining the necessary moisture for efficient gas exchange.

What is the main reason the size of insects is limited?

• Because they have mucus in their trachea

• Because they have a closed circulatory system

• Because oxygen is transported by blood

• Because they rely on diffusion for oxygen to reach each cell

Answer explanation

The main reason the size of insects is limited is because they rely on diffusion for oxygen to reach each cell, which becomes less efficient as the insect grows larger.

Why don't mammals and insects get the maximum amount of oxygen out of the air?

• Because they have a closed circulatory system

• Because the air goes in and out the same way

• Because they use air sacs to store extra air

• Because they have mucus in their trachea

Answer explanation

Mammals and insects don't get the maximum amount of oxygen out of the air because the air goes in and out the same way, limiting the efficiency of oxygen extraction.

How do insects adapt when they are losing too much moisture?

• By opening their spiracles wider to take in more air

• By closing their spiracles and using oxygen from their air sacs

• By increasing the production of mucus in the trachea

• By relying more on their circulatory system

Answer explanation

Insects adapt by closing their spiracles and using oxygen from their air sacs to prevent further moisture loss.

What makes the gas exchange system in mammals more efficient than in insects?

• The presence of air sacs

• The ability to open and close spiracles

• The use of mucus to keep the gas exchange surface moist

• The transport of oxygen by blood

Answer explanation

The transport of oxygen by blood is what makes the gas exchange system in mammals more efficient than in insects.

What happens when mammals have a higher energy demand?

• They pass more air through their lungs

• They rely on diffusion to transport oxygen to every cell

• They use air sacs to meet their oxygen needs

• They close their spiracles to conserve oxygen

Answer explanation

When mammals have a higher energy demand, they pass more air through their lungs to meet their oxygen needs.

What role does the diaphragm play in mammalian respiration?

• It contracts to decrease lung volume and expel air.

• It relaxes to help air enter the lungs more easily.

• It contracts to increase lung volume and draw air in.

• It assists in the diffusion of gases in the alveoli.

Answer explanation

The diaphragm contracts to increase lung volume and draw air in during mammalian respiration.

How does the structure of alveoli support gas exchange in mammals?

• By increasing surface area with a spherical shape.

• By decreasing surface area to minimize gas exchange.

• By moving gases through active transport.

• By relying on the presence of mucus to trap oxygen.

Answer explanation

The structure of alveoli supports gas exchange in mammals by increasing surface area with a spherical shape, allowing for efficient exchange of oxygen and carbon dioxide.

Why is a moist gas exchange surface important for efficient gas exchange?

• It allows gases to dissolve and diffuse more readily.

• It prevents the exchange surfaces from drying out and cracking.

• It traps harmful particles and pathogens.

• It cools the exchange surfaces, reducing energy demand.

Answer explanation

A moist gas exchange surface is important for efficient gas exchange because it allows gases to dissolve and diffuse more readily.

What mechanism do fish use for gas exchange?

• By using gills that extract oxygen from water.

• By using lungs to inhale air from the surface.

• By absorbing oxygen through their skin.

• By opening and closing spiracles to control air flow.

Answer explanation

Fish use gills to extract oxygen from water for gas exchange.