Answer: It was obtained 8515 years ago
Explanation:
Expression for rate law for first order kinetics is given by:

where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) to find the rate constant:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.


b) for completion of 36% of reaction


t = 8515 years
The time was 8515 years.
Is this like on a test or like homeowork?
Answer:
CENTROMERE
Explanation:
The CENTROMERE is the primary constriction region where the identical DNA molecules are most tightly bonded to each other during mitosis and meiosis.
The typical chromosome in metaphase is composed of two sister chromatids joined by the centromere.
Surrounding the centromere, we can find the kinetochores. These are laminar proteinic structures forming a plate where the spindle and kinetochore fibers will join during chromatids separation.
The position of the centromere defines the chromosomes as acrocentric, metacentric, or submetacentric.
effect is from the modification of land surfaces. Waste heat generated by energy usage is a secondary contributor.
Mutualism is relationship that is beneficial to both organisms involved. The relationship between a plant and a bacterium called a mutualism because both of them help each other. Bacteria are involved in increasing the fertility of the soil by fixing atmospheric nitrogen and thus provide plant with nitrogen. In return, the bacteria make their homes in what usually become nitrogen "nodules" along plant roots. The plant gets food, the bacteria gets shelter, everybody wins.