Answer:

Explanation:
An element only has <u>one</u> type of atom and cannot be broken down by chemical means.
Let's analyze the answer choices.
1. This has two types of atoms, so it cannot be an element. It has more than one type of atom.
2. This has two types of atoms that are bonded together. It cannot be an element because there is more than one type of atom and the bonds can be broken.
3. This has one type of atoms, so it is an element.
Therefore the best answer choice is 3.
Volcanic mountains,
Let me know if i'm wrong.:)
Answer:
Without fires, there would be no life on Earth
. Fires are key to maintaining the proper oxygen concentration in the atmosphere; fire regulates the carbon cycle and life, as we know it, is based precisely on carbon
Explanation:
Although we tend to think of fires as a human invention that kills plants, animals, people, fire, as with rain or wind, is an essential natural component, basic to maintain the planet's biodiversity.
As for example, grassland ecosystems are also benefited by the same fires that allow renewal, and generate natural sustainability on the earth through the carbon cycle.
The epidural anesthesia is a method of pain relief, which is used during the labor pain. It is a well known regional anesthesia. It works by acting as an analgesic, which means a substance that eases the pain, a complete anesthesia or loss of feeling does not occur in the case of epidural anesthesia. It blocks the nerve signals from the lower spinal segments. It is also known as spinal epidural anesthesia or lumbar epidural anesthesia.
Hence, the black can be filled with lumbar.
When you take blood pressure, it is expressed in a fraction. The top number of that fraction is systolic pressure- the amount of pressure in your arteries during contraction of your heart muscle... I hope this helped! :)