Naturally occurring uranium is a mixture of 238u (99.28%) and 235u (0.72%) isotopes. i) how old must the material of the solar system must be if one assumes that at its creation both isotopes were present in equal quantities? how do you interpret this result? the age of the planet earth is estimated at 4.5 billion years. the lifetime of 235u is t235 = 1.015 ~ 109 years. the lifetime of 238u is t238=6.49 ~ 109 years. ii) obtain the fraction of the initial 238u amount that has decayed since the formation of the earth's crust 2.5 x 10'years ago?

In 1859, charles darwin published the first edition of on the origin of species, which explained his observations of various groups of animals that showed great similarities but minor differences. darwin concluded that if a population of one species separates into two different populations that live in separate locations, then over the course of many generations the different populations can develop into different species. this idea predicted many future biological findings and became the basis of modern biology. darwin’s explanation for why different species exist is best described as a(n) law. theory. inquiry. hypothesis.