I'll give you the first one: it's a reactant of respiration. if you want the other answers just dm me so its easier to communicate
Answer:
D. Columnar
Explanation:
Hint the root word is in the option and it is actually shaped like a column according to Epithelium - Wikipedia
Hope this helps : )
Answer:
Explanation:
Basically its when tiny molecules float across the membrane from the lowest concentration to the highest concentration to get what they need like glucose.