Answer: Absolute dating is used to determine a precise age of a rock or fossil through radiometric dating methods. This uses radioactive minerals that occur in rocks and fossils almost like a geological clock. ... These isotopes break down at a constant rate over time through radioactive decay.
 
        
             
        
        
        
B). light energy is not required to proceed
Explanation:
In the Calvin cycle of photosynthesis, light energy is not required. The Calvin cycle is light independent and it is made up of a series of redox reactions. 
- During photosynthesis reactions, green plants manufacture their food using carbon dioxide, sunlight and water. 
- During the Calvin cycle aspect, light energy is not required for chemical reactions to take place. The light energy helps to move electrons. 
- The cycle is also known as dark reactions. 
- It is at this stage that carbon dioxide combines with water to form glucose. 
- The reaction is initiated with light energy which produces NADPH and ATP.
- The Calvin cycle follows by using the NADPH and ATP to produce glucose in the dark phase. 
Learn more: 
ATP brainly.com/question/2953868
Light dependent reactions brainly.com/question/6866300
#learnwithBrainly
 
        
             
        
        
        
The following are scientific observations which led to development and changes of periodic table: Dmitri Mendeleev is the first periodic table organized 63 known element according to its properties, organized into rows and columns and inscribed name, mass and chemical properties on each element. Julius Lothar Meyer who independently worked in Germany with Ernest Rutherford. They experimented with 38 metals and found out that the positive charge of each element nucleus increased by one from element to element and organized the periodic table that tip to modern explanation of atomic number and the recognition of atomic number was the basis for organization of periodic table.
        
             
        
        
        
Alkali metals are known for being some of the most reactive metals. This is due in part to their larger atomic radii and low ionization energies. They tend to donate their electrons in reactions and often have an oxidation state of +1. These metals are characterized as being extre
        
             
        
        
        
1. Physical matter 
2. Chemical matter
3. Physical matter 
4. Physical matter
5. Chemical matter 
6. Physical matter.