The alveoli are surrounded by tiny blood vessels, called capillaries carrying blood to and from the heart.
Carbon dioxide (CO²) is taken in to start the Calvin Cycle.
The
two categories that are used to classify physical changes are Reversible and
Irreversible.
Reversible
means that the matter can convert to gas, liquid and solid and then convert
back to gas, liquid or solid. So it means it can convert back and forth.
<span>Irreversible
means that matter cannot be converted back as it is before.</span>
