Edexcel GCSE Combined Science CB8 and CB9 Exchange, transport and ecosystems overview quiz quiz

They have a large surface area to volume ratio, so simple diffusion across the outer surface is more than enough for them

They do not respire, so they have no need to exchange any gases with their surroundings at all

They have a small surface area to volume ratio, so diffusion across the outer surface is not enough

They do not need oxygen, so no exchange surface is required

Thick walls that slow down the diffusion of gases across them

A dry surface that keeps the gases from dissolving

No blood supply, so gases are not carried away

A large surface area and walls one cell thick

Twice

Once

Three times

Four times

The left side

The right side

Both ventricles together

The atria only

Plasma

White blood cells

Red blood cells

Platelets

Respiration carried out by living organisms

Combustion of wood and fossil fuels

Decomposition of dead remains by microbes

Photosynthesis

Light intensity

A predator

Availability of food

A disease

To break down the dead remains of plants and animals in the soil

To turn nitrogen gas into compounds that plants can use

To return nitrogen gas to the air

To carry out photosynthesis in the soil

The number of plant species only, ignoring all the animals present

The total mass of producers

The variety of different species in an ecosystem

The amount of rainfall

Conservation

Replanting forests

Creating nature reserves

Deforestation

To avoid bias so the sample is representative

To save time when surveying a very large area of ground

To make sure the quadrats land on the largest plants present

To make the calculations afterwards much easier to do

A vein

An artery

A capillary

The vena cava