If a radioactive nuclide has a half-life of 1.3 billion years, and it is determined that a rock contains 50% of its original amount of this nuclide, about how old is the rock?

Age of rock is 1.3 billion years

Explanation:

The half life of radioactive nuclide is 1.3 billion years

let us say that the original quantity of rock once upon a time would have been 100%

Half life period means the period in which the quantity of radioactive substance with in the nuclide reduces to half its original value.

Thus, time taken by nuclide to reduce to 50% of its original amount (i.e 100%, once upon a time) is 1.3 billion years.

Hence, it can be concluded that the time at which the nuclide has exactly 100% of its original amount would be 1.3 billion years.

Thus, the age of rock is 1.3 billion years.

the titanic would be the correct answer

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.