Answer: 2948
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = age of sample = ?
a = let initial amount of the reactant = 100
a - x = amount left after decay process = 
Thus the fossil is 2948 years old.
Constricted blood vessels
True
Explanation:
Harry Hess in 1961 resurrected Wegener's continental drift hypothesis and also he mantle convection idea of Arthur Holmes by postulating the theory of sea floor spreading.
- After Wegener's postulation of the continental drift hypothesis, not much was done.
- It was only around 1931 that Arthur Holmes came up with the idea of a convecting mantle.
- After the second world war passed, new instruments were used to investigate and map the ocean floor.
- Through this, Arthur Holmes came up with the idea of a spreading sea floor.
- This gave a full gleam picture to the idea of a moving earth and the more accepted terminology of "Plate tectonics " came to the fore.
Learn more:
Sea floor spreading brainly.com/question/9912731
Continental drift brainly.com/question/5002949
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