Top answers

Describe and explain how the lungs are adapted to allow rapid exchange of oxygen between the air in the alveoli and blood in the capillaries around them. (5 marks)

The lungs have million of alveoli which increases the surface area , therefore increasing the rate of diffusion of oxygen into the lungs. The alveoli are very thin walled , which reduces the diffusion pathwa...
AZ
Answered by Aysha Z. • Biology tutor
13927 Views

Describe the pressure and volume changes in the lungs during inspiration

During inspiration, the intercostal muscles contract, moving the sternum up and out. This increases the thoracic volume, hence decreasing the pressure. The pressure gradient set up causes air inflow from out...
DN
Answered by Dhaval N. • Biology tutor
4554 Views

Describe the trends in predator and prey populations seen within a community in an ecosystem

Prey population size increases when there are enough resources available for food. When prey populations increase, the predator population size also increases, as this means there is more food available for ...
OC
Answered by Olivia C. • Biology tutor
8946 Views

What benefits does compartmentalisation confer on cells?

Intro: Look at caveats in the question:Not all cells are compartmentalised - e.g. prokaryotic cellsThis therefore tells us that compartmentalisation is likely an adaption to a set of biological niches.(If co...
GP
Answered by Guy P. • Biology tutor
11509 Views

Outline the circulation of blood and the physical changes of the heart during the cardiac cycle.

The cardiac cycle is split into 2 main phases: systole where the heart contracts and ejects blood out from the heart and diastole where the heart relaxes and fills with blood. The right side of the heart pum...
AM
Answered by Aishah M. • Biology tutor
3044 Views