Atria is a large part of the heart so too big for cells; arteries & veins lead away or to the heart.
Capillaries are the smallest vascular structures that allow materials to be exchanged easily between cells.
The slightest change in pH can destroy the substance or organism. The pH of a cell's interior helps regulate the cell's chemical reactions. For example, the pH of blood is 7.4, if blood falls to 6.8 or lower or 8.2 or higher, it results in death.
Chemical energy is stored in the battery cells and converted to electrical energy when it's needed by the toy robot
Answer:
d
Explanation:
bacteria is a small rna and there are millions of them they are not big enough to have dna
