Question

Age of fossils can be detected by
A. Residual quantity of calcium
B. Quantity of radioactive carbon compound
C. Phylum of other mammals
D. Structure of bones.

Answer 1

Hint: The preserved impression of living organisms are called fossils. After the death of the organisms, the bodies get decomposed and lost. We can detect the age of the fossils in two components of estimation. The first component is by digging into the earth and beginning to find the fossil. If we find the fossil in the upper layer it is a more recent fossil if we find in a deeper layer that fossil is older. The second component is by detecting the ratios of different isotopes of the same element in the fossil material.

Complete answer:
A. Residual quantity of calcium: Residual quantity of calcium can be detected by computer simulation.
So, option (A) is incorrect.

B. Quantity of radioactive carbon compound: The dead and decomposing in the soil settles in the lower surface of the soil and gets converted into fossils due to the pressure and temperature in the lower surface of the earth crust. The age of fossils can be detected by the number of radioactive carbon compounds. Determination of age of an object containing organic material by using the properties of radiocarbon can be detected by Radioactive dating. Radiocarbon dating is a method based on radiocarbon that is repeatedly created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. This radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is used by plants for photosynthesis, then animals take these 14C by eating the plants. When the animal or plant dies, it ends giving and taking of the gases with the environment, and from that time the amount of 14C begins to reduce as the 14C undergoes radioactive decay.
So, option (B) is the correct answer.

C. Phylum of other mammals: Phylum is a taxonomic ranking that comes in third in the hierarchy of biological classification, after domain and kingdom.
So, option (C) is incorrect.

D. Structure of bones: The structure of bones is an anatomical characteristic of bones.
 So, option (C) is incorrect.

Hence, the correct answer is option (B).

Note: The total amount of 14C in a sample from a dead plant or animal can be measured such as a piece of wood or a fragment of bones gives a piece of information that can be used to determine when the animal or plant died. In the older sample, we can detect less 14C because the half-life of 14C is about 5,730 years. The oldest can be relatively detected by using radiocarbon dating around 50000 years ago. This special preparation is occasionally permitted to measure older samples. By this method, we can detect the age of the fossils and minerals.