They are different because one is stronger than the other
Answer:
The fix nitrogen into free nitrogen which is a usable form. They also bring nitrogen back into the system by decomposing dead organisms.
Answer 2.
Because, they are known as nitrogen fixing bacteria. These organisms convert nitrogen in the soil to ammonia, which can then be taken up by plants. After nitrogen has been fixed, other bacteria convert it into nitrate, in a process known as nitrification.
Both answer is correct choose the best choice for you.
Hope this helps!
Answer:

Explanation:
Amount of water displaced by the sphere will be equal to the volume of complete sphere.
As the sphere completely sinks to the bottom of the cup.
We have been given;
Diameter of sphere (d) = 4.6 cm
So,

Volume of sphere (V):

By substituting value of r we get:

1 cm³ = 1 mL

V = 51 mL
So,
Water displaced by the sphere = 51 mL
Underwater living faces many of the same life support challenges as living in space. ... But in the future, underwater habitats might provide their own oxygen with artificial gill technology to extract dissolved air from the sea water
Since humans do not have gills, we cannot extract oxygen from water. Some marine mammals, like whales and dolphins, do live in water, but they don't breathe it. They have developed a mechanism to hold their breath for long periods of time underwater.
To put these depths into perspective, three American football fields laid end to end would measure 900 feet (274.32 m) long — less than the distance these divers reached underwater. Most recreational scuba divers only dive as deep as 130 feet (40 meters), according to the Professional Association of Diving Instructors.
Sirius B is brighter than the sun.