Answer:
Paleozoic
Explanation:
The first insect fossils are dated to the Devonian, but because of the development of the genetics, the scientists have been able to trace the appearance of the first insects in the Ordovician. The insects originated from the crustaceans. Initially they were walking on land, but they hadn't developed wings. The wings came to develop in some insects in the Devonian, and since than it has gradually became one of their trademark features. It is interesting that the first insects actually appeared at the same time with the first terrestrial plants, and also that they are the first organisms to develop wings and be able to fly.
Answer:
Australia
Explanation:
Because there are so many fires in Australia
Answer: Carbon
Explanation:Carbon is the element released by volcanic outgassing,animal respiration and flatulence,burning of fossil fuels and the metamorphism of limestone.
Volcanic outgassing is the release of carbon into the atmosphere mainly in the form of carbon monoxide.
Animal respiration and flatulence are process taking place in animals which leads to the release of carbon dioxide.
Burning of fossil fuels is the use of heat to breakdown fossil fuels such as petroleum leading to the release of Carbon.
Limestone metamorphism is the breakdown of limestone which leads to the release of Carbon to the atmosphere.
A C and D. It cannot be b because scientists have warned people in the past about volcanoes and their possibility for erupting. Earthquakes cannot be predicted however there are warning signs one can look for.
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
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Radioactive decay brainly.com/question/10125168
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