Question

this is 1 ____ ALVEOLUS. its walls are thin, and oxygen from inhalend air passes through. 2) __ oxygen is pickd up by blood that travelis -or circulates- to different parts of the body 3) __ artery carries blood with oxygen. 4) __ vein carries blood, with carbon dioxide

completar el siguiente texto con: a, an or the
urgnte, por favor

Answer 1

1. An
2. the
3. an
4. a

espero que te sirva