Answer: 2^(3^4)
Explanation: do the 3^4 first in the parentheses then do 2^81
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.
Answer:
Humans have some stem cells, but those cells are not easily available to help with healing. Most other mammals are the same, so they aren't good at regeneration either. Amphibians and some fish have stem cells that are more easily available, and are usually pretty good at regeneration.
Answer:
Chemical weathering
Explanation:
The weathering of rocks by chemicals is called chemical weathering . Rainwater is naturally slightly acidic because carbon dioxide from the air dissolves in it. Minerals in rocks may react with the rainwater, causing the rock to be weathered. Some types of rock are easily weathered by chemicals.
Definition of chemical weathering: the erosion or disintegration of rocks, building materials, etc., caused by chemical reactions (chiefly with water and substances dissolved in it) rather than by mechanical processes.
