Exchange of anything with blood (air, nutrient, hormones etc) occurs through blood capillaries. This is thanks to the simple squamous epithelium lining the walls of the capillaries.
Answer:
low concentration to high concentration
They are female because they have two X chromosomes (as you can see at the bottom right of the picture) If they were male they would have one X chromosome and one Y chromosome.
Answer:
The location in which it stores its genetic material.
Explanation:
