So that the mircrobes present could get help to perform anariobïc repiration (respiration without oxygen).....as it helpfull for decomposing the sewage waste ...also to prepare sideproduct called metane gas
Answer:
Boron family.
Explanation:
Group 13 is called boron family.
It consist of five members boron, aluminum, gallium, indium and thallium.
Boron is semi metal while other members are metals.
Boron hydrates are used to make organic compounds.
Al is soft metal and aluminum oxides are widely used as thermal insulator.
Aluminum sulfate is also very important commercial compound used in sizing paper.
Gallium is also very important element of this group. It form gallium arsenide which is used to convert the light into electricity.
Indium is malleable soft metal which is used in optical instruments.
Thallium is highly toxic and for the long period of time it as used as insect killing poison.
Answer: The average atomic mass of oxygen is 15.999 amu
Explanation:
Mass of isotope O-16 = 15.995 amu
% abundance of isotope O-16= 99.759 % = 
Mass of isotope O-17 = 16.995 amu
% abundance of isotope O-17 = 0.037% = 
Mass of isotope O-18 = 17.999 amu
% abundance of isotope O-18 = 0.204% = 
Formula used for average atomic mass of an element :
![A=\sum[(15.995\times 0.99759)+(16.995\times 0.00037)+(17.999 \times 0.00204)]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%2815.995%5Ctimes%200.99759%29%2B%2816.995%5Ctimes%200.00037%29%2B%2817.999%20%5Ctimes%200.00204%29%5D)
Thus the average atomic mass of oxygen is 15.999 amu
Answer:
When an experiment is replicanle it means it is able to be done again.
Explanation:
It is important because You need to see if you get different results or if you messed up the first time
Concave is not a type of mechanical wave because it doesn’t need a medium for propagation.
