What materials? There are none provided.
Lithosphere: rocks and minerals
Hydrosphere :different forms of water
Atmosphere: oxygen and gases
Cryosphere: Ice
Biosphere: plants, animals and humans
Answer:
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Answer:
A = 4000 years
Explanation:
Given data:
Half life = 2000 years
Total mass = 100 g
Mass remain = 25 g
Time taken to reduces to 25 g = ?
Solution:
At time zero = 100 g
At first half life = 100 g/2 = 50 g
At 2nd half life = 50 g / 2 = 25 g
Time taken:
Half life = Time elapsed / number of half lives
2000 years = Time elapsed / 2
Time elapsed = 2000 years × 2
Time elapsed = 4000 years