Answer: scientific theory is an explanation of observations or events that is based on knowledge gained from many observations or events.
What percent of potassium-40 remains undecayed in a rock that is 3.9 billion years old? The 3.9 billion year old rock has undergone three half-lives (3.9 divided by 1.3 = 3). After 3 half-lives, 12.5% of the potassium-40 remains undecayed.
Your answer is A. during an extended surgical procedure
Answer:
Mechanical Weathering
- caused by freezing and thawing of of water.
- caused by the movement of agents such as glaciers and wind.
Chemical weathering
- caused by processes such as corrosion, hydrolysis and dissolution.
- caused by precipitation reacting with minerals in the rock.
- creates new substances such as clay and salts.
