Answer: A
Explanation:
Isotopes of different elements differ by the number of neutrons inside the nucleus.
The characteristic of epithelial cells that makes them ideal for providing this type of protection is that the cells are packed tightly together.
Skin, the body's largest organ,is our first and best defense against external aggressors. The many layers work hard to protect us, however when its condition is compromised, its ability to work as an effective barrier is impaired.
The element is iridium and it has 77 electrons
Answer:

Explanation:
Gravitational potential energy is the energy an object possesses due to its position. It is the product of mass, height, and acceleration due to gravity.

The object has a mass of 150 kilograms and is raised to a height of 20 meters. Since this is on Earth, the acceleration due to gravity is 9.8 meters per square second.
- m= 150 kg
- g= 9.8 m/s²
- h= 20 m
Substitute the values into the formula.

Multiply the three numbers and their units together.


Convert the units.
1 kilogram meter square per second squared (1 kg *m²/s²) is equal to 1 Joule (J). Our answer of 29,400 kg*m²/s² is equal to 29,400 Joules.

The crate has <u>29,400 Joules</u> of potential energy.