What is the approximate percentage of geologic time that humans have existed on Earth since its origin?
A) less than 1%
B) 1.8%
C) 11.8%
D) more than 25%
О А
О в
Ос
○ D



Answer :

To find the approximate percentage of geologic time that humans have existed on Earth since its origin, we need to follow these steps:

1. Identify the relevant time periods:
- Years humans have existed: Approximately 200,000 years.
- Age of the Earth: Approximately 4.54 billion years (which is 4.54 × 10^9 years).

2. Set up the percentage calculation formula:
[tex]\[ \text{Percentage} = \left( \frac{\text{Years humans have existed}}{\text{Age of the Earth}} \right) \times 100 \][/tex]

3. Plug in the values:
[tex]\[ \text{Percentage} = \left( \frac{200,000}{4.54 \times 10^9} \right) \times 100 \][/tex]

4. Perform the calculations:
- First, divide 200,000 by 4.54 billion.
[tex]\[ \frac{200,000}{4.54 \times 10^9} = \frac{200,000}{4,540,000,000} \approx 4.4052863436 \times 10^{-5} \][/tex]
- Then, multiply by 100 to convert the fraction to a percentage.
[tex]\[ 4.4052863436 \times 10^{-5} \times 100 \approx 0.0044052863436 \% \][/tex]

5. Round the result to make it more comprehensible (if necessary):
- The result [tex]\(0.0044052863436\%\)[/tex] is already very small and accurate enough for our purposes.

6. Compare the calculated percentage with the given options:
- Less than 1% (A)
- 1.8% (B)
- 11.8% (C)
- More than 25% (D)

From our calculation, we can see that 0.0044052863436% is significantly less than 1%.

Therefore, the approximate percentage of geologic time that humans have existed on Earth is:
A) less than 1%