Mitochondria and chloroplasts likely evolved from engulfed prokaryotes that once lived as independent organisms. 
(At some point, a eukaryotic cell engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host eukaryote, gradually developing into a mitochondrion. Eukaryotic cells containing mitochondria then engulfed photosynthetic prokaryotes, which evolved to become specialized chloroplast organelles).
        
                    
             
        
        
        
Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals, rather than the preserved remains of the body of the actual animal itself.
 
        
             
        
        
        
Answer:
Axon hillock
Explanation:
Neuron or nerve cell is excitable cell of the nervous system which consists of cell body or soma (karyon), dendrites and an axon. Dendrites are short, numerous filaments responsible for the signal receiving. On the other hand, axon is long ant it originates form the cell body from the swelling called axon hillock. At the end of an axon there are axon terminals from which neuron can transmit a signal  another cell. 
 
        
             
        
        
        
Answer:
amino acids
anaerobic respiration
aerobic respiration
lungs
liver
kidneys
nitrogen
toxic
Explanation:
Excretion refers to the removal of waste products that is produced from amino acids metabolism.
Carbon dioxide is formed in living organisms in the process of both aerobic respiration and anaerobic respiration and can be removed from the body through lungs.
Urea is produced in the liver and then the blood is to be sent to the kidney and which is excreted from the body.
Urea is compounds of nitrogen which is formed from amino acids that contains toxic substances which the body does not need.
 
        
             
        
        
        
The answr is c. Facilitated diffusion