The Half life is the time taken for a radioisotope or a radioactive substance to decay by half its original amount. The half life of carbon 14 is 5600 years.
Original mass is 100%
Remaining amount is 24%
Therefore; 0.24 = 1 × (1/2)^n
n = log 0.24/log 0.5
= 2.06
therefore, the age of the fossil is 5600×2.06
= 11529.8
≈ 11529 years
<u>Answer:</u>
Earth's axis and position around the sun.
<u>Explanation:</u>
Earth's tilted axis causes the seasons to change. Throughout the year, different parts of Earth acquire the Sun's most direct rays(Or heat) because of the orbital rotation of Earth. So, when the North Pole tilts toward the Sun, it's summer inside the Northern Hemisphere. And whilst the South Pole tilts towards the Sun, it is winter within the Northern Hemisphere and vise versa.
Answer: There are 0.000043 moles of melatonin.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
given mass = 10 mg = 0.01 g
molar mass of 
= 232.28 g
Thus there are 0.000043 moles of melatonin
Question 1 answer: A
Question 2 answer: H
Question 3 answer: J
Question 4 answer: T
A vibrating string can create longitudinal waves as depicted in the animation below.
The answer is C) vibrations
