Answer:
20% of worlds population survive on 1 dollar a day
Due to rapid urbanization fueled by trade, approximately 87 percent of people live in urban areas of Australia. The correct option among all the options that are given in the question is the first option or option "A". A large part of Australia is covered in jungle and so major cities are places where people flock the most.
More than 75 percent
Explanation:
Let us carefully analyze this problem:
The half life of the rubidium isotope = 50 billion years
The half-life of a radioactive isotope is the time it takes for it to decay to half of its original amount.
Every 50years, we know that a rubidium isotope would split into half.
Initially when the isotope was formed, we would only have the parent atoms there. There wont be any daughter;
ratio of parent to daughter = 100 : 0
When the isotope decays to half; we would have equal number of parent and daughter:
ratio of parent to daughter at half life = 50 : 50
The age of the earth is about 4.6billion years;
this is;
x 100 = 9.2% of the half-life of the rubidium isotope.
At this time, we should know that only 9.2 percent of the daughter would have been formed.
The remaining parent would be 100 - 9.2 = 90.8% would still be left undecayed.
The ratio of parent to daughter = 90.8 : 9.2
This is more than 75% of the parent
learn more
Radioactive decay brainly.com/question/10125168
#learnwithBrainly
C. Law of superposition because it is the principle that the oldest layer of sediment will be found on the bottom
Density, population size, and distribution statistics.