Answer:
The correct answer is option - C. They replaced carbon dioxide with oxygen in the atmosphere.
Explanation:
Cyanobacteria or Blue-green algae is a group of bacteria that is making its own food using water and carbon dioxide in the presence of sunlight, the process of photosynthesis
These organisms release oxygen as a byproduct of photosynthesis in the atmosphere. Through this process, these organisms replaced carbon dioxide with oxygen in the atmosphere in the early earth.
Thus, the correct answer is option C. They replaced carbon dioxide with oxygen in the atmosphere.
 
        
             
        
        
        
Given the answers;
a) Reptiles
b) Cactus plants
c) Small birds 
d) Crabs and crayfish
The answer is C. Small birds.
On his visit to the Galapagos Islands, Charles Darwin discovered several species of finches that varied from island to Island, which helped him to develop his theory of natural selection. 
        
             
        
        
        
The stages of mitosis are:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase<span>
Prophase
This is when the </span><span>centrioles separate and move to opposing sides of the cell.
Metaphase
This is when the chromosomes line up in the center of the cell and become connected.
Anaphase
This is when the</span><span> "sister" chromatids separate into individual chromosomes and are pulled apart.
Telophase
This is the last phase of mitosis, when chromosomes gather at opposite ends of the cell and new nuclear membranes form.
The answer is metaphase, because that is when the chromatids line up in the center of the cell.
Answer:
Metaphase</span>
        
             
        
        
        
Answer:
Hydrotropism and gravitropism work together and are difficult to separate from one another.