<span>organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere. These have been arranged from the smallest to the largest. The biosphere is the largest level of organization while the organelle is the smallest. However, the basic form of life begins with the cell. Many cells together form a tissue and several tissue form an organ.
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Answer:D
Explanation: The pulmonary air sacs of birds only permit a unidirectional flow of air through the lungs. Unidirectional flow means that air is inhale and exhale through one trachea alternatively. This means the bird lungs only receive largely fresh air which has a high oxygen content during inhalation and do not receive fresh during exhalation. While air flow bidirectional in mammals.
 
        
             
        
        
        
A fixed action pattern
is a behavior that is carried out to completion once started, regardless of
changes in the original stimulus and the sequence is unchangeable. The
unlearned behavior of fixed action patterns are triggered by a type of external
stimulus that start off a particular organism.
  
 
 
        
             
        
        
        
Answer:
Explanation:
Electromagnets. Electromagnets are a different from permanent magnets. Electromagnets are made of coils of wire with electricity passing through them. Moving charges create magnetic fields, so when the coils of wire in an electromagnet have an electric current passing through them, the coils behave like a magnet.