Answer:
From my guess it is probably option J.
Answer:
The correct answer is 4.6 percent.
Explanation:
The Oort cloud refers to the clouds of icy objects, which is present in the outermost section of the solar system. These are the disperse layer of clouds found in the external layer of the solar system.
In the given question, it is given that the number of comets in the Oort cloud is 10^12 comets.
The number of comets getting close towards the Sun is 10 comets in a year.
The age of the solar system is 4.6 * 10^9 years
The number of comets used since the start of the solar system is,
(4.6 * 10^9 years) (10 comets/year)
= 46 * 10^9 comets
Thus, the number of comets disappeared since the beginning of the solar system is 46 * 10^9 comets.
The initial number of comets at the start of the solar system is 10^12 comets.
The percentage of comets that are used up are:
(change in no of comets) / (initial no of comets) % = (46 * 10^9 comets) / (10^12 comets) * 100
= 4.6 percent.
Correct answer: True
The coral reefs are made up of thousands of tiny animals called as polyps. These are related to anemones and jellyfish. It possesses a sac-like a body and an opening which is encircled by the stinging tentacles called as cnidae.
They use calcium and carbonate ions which are derived from the seawater to in order to make a hard, cup-shaped skeleton. It protects the soft and delicate body of the polyp.
Hence, the correct answer would be true
