Answer:
Using the concept of relative dating
Explanation:
Scientists use the concept of relative dating principles to determine when the Great Oxidation event occurred. 
Relative dating is the process of placing ancient event in their proper time sequence based on the relationship between rock lithologies. 
- An event like the great oxidation will have significant chemical, biological and physical effect on the rock units. 
- Rocks that form during this period in time will have very unique chemical signatures. 
- Therefore, by studying these rocks, the age of the layer can be fixed when we compare it to the standard geological column. 
 
        
             
        
        
        
The correct answer is - B. Beak size determines what the bird can eat.
The beak of a bird can come in many different shapes and sizes. It can be pointy, long, short, rounded, scythe-like, thin, thick... All of those shapes and sizes have a specific role, and that role is to enable the bird to feed itself with certain type of food source. Every food source requires certain type of beak in order for the bird to be efficient in getting its nutrition, so depending on hat the bird eats, we can easily see a pattern in the beaks, where birds that eat nuts have one strong and shorter beak, the ones that eat warms and insects have thin, pointy one, the predator birds have claw like, sharp beak...
 
        
             
        
        
        
Answer:
C. Oxygen & Hydrogen. 
Explanation:
The body is made of 65% Oxygen, 18% Carbon, 10% Hydrogen, 3% Nitrogen, and 4% other elements. 
 
        
             
        
        
        
Answer:
please give me brain list and follow
Explanation:
The main function of the cell nucleus is to control gene expression and mediate the replication of DNA during the cell cycle. The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material.
 
        
             
        
        
        
The smallest item in the list would be organelles. Organelles are tiny structures within a cell, that help it to function. Example of organelles are-- nucleus, mitochondria, cell membrane to name a few. Cells are the basic unit of structure and function of all living things, therefore, cells would have to be placed second. They are microscopic. A group of similar cells that work together to perform a specific function, is known as a tissue. Therefore, tissue is next largest. Examples of tissues include, muscle tissue, epithelial tissue, adipose tissue. When different types of tissues work together to perform a function in the body, this group of tissues forms an organ. An example of an organ is the heart. Inside the heart are many types of tissue-- cardiac muscle,nerve, blood, connective, etc. The job it performs is to pump blood. When various organs work together to perform a specific function in the body, this makes up a system. An example is the circulatory system. In this system are many organs that work together. Arteries, veins, capillaries and heart are all part of the circulatory system. Its job is to circulate blood containing nutrients and oxygen to cells and to pick up cellular wastes. All the systems of the body comprise the organism. An organism is a living thing. It can be as tiny as a microbe, or a complex as a human. When referring to a multicellular organism, the correct order from smallest to largest is-- organelle, cell, tissue, organ, system, organism