<span>The number of protons plus the number of neutrons is called the mass number.</span>
hope this helps
I do think that they close to not allow too much of either water or air from entering.
the hollow tube allows water to flow easily.
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/1
Answer:
less than 1%
Explanation:
The approximate percentage of the geologic time that humans have existed on the Earth since its origin is less than 1%.
The earth is about 4.6 billion years and much of its history has been without the present of human activities.
- Hominis were the first human to appear on the surface of the earth.
- This was in the Miocene epoch which was about 6 million years ago.
- Compared to the age of the earth, this time lapse is very small and not up to 1%.
- Life first appeared on earth about 3.5billion years.
- Since then evolution has taken its due course to give what we have today.
Answer: The correct answer is black because the product of its side and mass is lower.
Explanation: Density of a substance is defined as the mount of matter that can be stored in a given volume.
Mathematically,
As, density is inversely proportional to the volume of the substance.
The substance will be more denser if it has less volume and it will be less denser if the volume is more.
We are given two cubes having different sides.
Volume of the cube is calculated by using the formula:
where, a = side of the cube.
Black: The side of this cube is 2 and volume will be =
Yellow: The side of this cube is 3 and volume will be =
As, the volume of black cube is less. So, this cube will be more denser.
Density of black cube:
Density of Yellow Cube:
Hence, black cube will be more denser because the product of its side and mass is lower.
Answer: A.They contain plants that purify water.