The compound that was formed by the reaction of the first oxygen released by Cyanobacteria and iron are the metals of the earths crust. Cyanobacteria was the first organisms that used water instead of hydrogen sulfide or other compounds as a source of electrons and hydrogen for fixing carbon dioxide. Early Cyanobacteria inhabited marine sediments where Archean banded iron formations were deposited; consisting of reddish layers rich in iron oxide. 
        
             
        
        
        
Answer:
Answer 1: The correct answer is b. convergent continental-continental boundary.
A convergent continental-continental boundary refers to a convergent plate boundary where two continental plates meet or come together. When this happens, a forceful collision occurs, and structures like mountains start to form. The Himalaya mountain range is formed as a result of the convergence of the Indian and Eurasian continental plates.
Answer 2: The correct answer is d. convergent oceanic-oceanic boundary.
Volcanic island arcs refers to a curved line of volcanoes formed from the subduction (sinking) of one oceanic plate below another plate. Examples of volcanic island arcs include Japanese Islands and Alaskan Islands
 
        
             
        
        
        
The approximate alcohol content is 210 ml.
Explanation:
It can be deduced from the question that each bottle is of 1000ml or 1 litre.
The first bottle is one half full means it has 500 ml of solution and it has 20% alcohol in it. So volume of alcohol in the solution is
20/100*500
=100 ml 
The first bottle is one fifth full, so the volume of mixture is 1/5th of 1000ml
so it is 200ml having 30% alcohol
30/100*200
= 60 ml
The third bottle is one tenth full so its volume is 1/10*1000
100 ml.  having 50% of alcohol
50/100*100
50 ml.
The alcohol content obtained from all these 3 litres is:
100+60+50
= 210 ml of alchohol is obtained from 800 ml of mixture.
 
        
             
        
        
        
Answer:
B-29
Explanation:
Since there are 29 positive charges in the nucleus, there must be 29 negative charges. And cause the atomic number of copper is 29.