Answer : Hydrogen.......:
        
             
        
        
        
The statements that describe steps taking place in the nitrogen cycle are 
- Many biotic and abiotic factors play a role in recycling nitrogen ( A )
- Farming practices and chemicals lead to a build-up of nitrates in the soil ( E )
Nitrogen cycle is biochemical process whereby nitrogen is converted to various chemical forms as it passes through the atmosphere, Marine and terrestrial ecosystems .
Nitrogen cycle undergoes four ( 4 ) important processes which are :  
- Fixation
- Ammonification
- Nitrification and 
- Denitrification
Hence we can conclude that The statements that describe steps taking place in the nitrogen cycle are :
Many biotic and abiotic factors play a role in recycling nitrogen and 
Farming practices and chemicals lead to a build-up of nitrates in the soil 
Learn more about Nitrogen cycle : brainly.com/question/1380063
 
        
             
        
        
        
1. The central nervous system including brain and spinal cord.
2. The peripheral nervous system including nerves coming out from the brain and spinal cord, i.e., cranial nerves and spinal nerves.
3. The autonomic nervous system including sympathetic nervous system and parasympathetic nervous system.
 
 
        
                    
             
        
        
        
Answer: 
rock that forms when melted rock (magma, lava) cools and hardens
Explanation: 
Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust.
Brainliest plz
 
        
             
        
        
        
Answer:
properties cell membranes