Symbiosis is the ecological relationship between two or more organisms living closely together with some form of feeding relationship involved. The three main symbiotic relationships are: - Mutualism, where both organisms benefit. - Commensalism, where one organism benefits while the other organism is not harmed. All of them thrive off of the other organism.
        
             
        
        
        
1 Down: Aorta
2 Down: Blood
3 Across: Circulatory
3 Down: Capillaries
4 Down: Oxygen
5 Across: Systemic
6 Across: Ventricles
6 Down: Valves
7 Across: Heart
8 Across: Veins 
I hope this helps! Please give brainliest and thanks if you can
        
             
        
        
        
As most microbes reproduce asexually, "species" are defined by differences in their DNA sequences. when the genome of soil microbe a is analyzed, long stretches of genes from multiple species of other soil microbial species are discovered. This indicates that the microbes present in the soil underwent transformation and transfection. Transformation, shown in the image, is the process of the prokaryotic nucleus taking up the foreign DNA from other microbes present in the environment. Tranfection is like transformation but for the eukaryotic cells. 
 
        
                    
             
        
        
        
1)ocean
2)turning dark skin darker
3)tundra plant have a life span of only 1-2 month
4)it is rich with water and oxygen 
5)planetary devastation All Mighty Push
        
             
        
        
        
Earth's tilt on its axis affects the way heat is distributed on Earth's surface.
The Earth orbits the sun every 365 ¼ days. The Earth is tilted 23.5 degrees on its axis, which affects the distribution of the sun’s energy across the surface of the planet. More tilt means more severe seasons, that is warmer summers and colder winters where as less tilt means less severe seasons, that is cooler summers and milder winters.
Find out more on earth tilt at: brainly.com/question/818630