What are blood capillaries?

Blood capillaries are the smallest blood vessels having single cell layer of epithelia and is interwoven throughout the body tissues.

What are C4 plants?

C4 plants are those plants which can photosynthesize in hot and dry climates at a faster rate than the C3 plants due to special leaf anatomy and a unique biochemical pathway which includes fixing of sunlight energy that is the photons into four carbon containing sugar intermediate.

What is an Alveolus?

Alveolus, it is the unit of respiration, it is any of the tiny, blind-ended cavities in lungs in which gas exchange takes place.