Question

The age of fossils was previously determined by radioactive elements. A more precise recent method which has led to the revision of evolutionary periods is
(a) Study of carbohydrate and protein in fossils
(b) Study of conditions of fossilization
(c) Electron spin resonance and fossil DNA
(d) Presence of carbohydrate and protein in rocks

Answer 1

The age of fossils was previously determined by radioactive carbon dating. Recent developments in this field to give more precise results or the age of fossils have evolved to make the process more specific. This method was introduced in 1975. It is based on the presence of unpaired spins of charges. It was first introduced by Motoji Ikeya of Japan.

Complete answer:
More precise recent method which has led to the revision of evolutionary periods is Electron spin resonance and fossil DNA. Electron spin resonance measures the number of unpaired electrons or charges in crystalline structures that were exposed to natural radiation. Electron spin resonance is also used in coral reef dating and tooth enamel dating.

Additional Information: - Electron spin resonance measures the change in microwaves with a continuously changing magnetic field and thus measures the number of unpaired charges trapped in the lattice.
- Radioactive carbon dating was based on the decay of materials in the observed time period. So, the age of fossils was determined by carbon dating on the fact what the amount of material has decayed.
- The age of the substance is determined by measuring the dosage of radiation since the time of its formation.
So, the correct answer is electron spin resonance and fossil DNA.

Note: Electron spin resonance is used in biochemistry, radiation chemistry, geology, archaeology, and anthropology. The age of trees is determined by measuring the annual rings formed during different seasons. The activity of vascular cambium is high in the spring season makes springwood and has a lower density of wood and wood with a higher density is darker in color, this makes distinct colored rings so annual rings are counted.