Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
Answer:
B. Warm front
Explanation:
A warm front weather forecast, when a cold weather is preceded by a warmer weather it is known as a warm front.
Answer:
A. technology can be used to overcome physical barriers and boundaries
Explanation:
The ability to dam water and use of improved transportation are clear proofs of how we can overcome physical barriers and boundaries.
- Dam water is an engineering revolution by which water can be made available all year round.
- Also, damage to the ecosystem caused by excess water is circumvented.
- Roads that are pliable are of huge important in breaching geographical imitations. A good transport system can make use of this connectivity.
- Air transportation has improved the ease of travel and reduced travel time greatly.
- Both dams and good transportation are clear engineering solutions to overcome limitations of nature.
Answer:
Non-bird dinosaurs lived between about 245 and 66 million years ago, in a time known as the Mesozoic Era.
hope this helps <3
