Answer:
Multicellular organism is the example of complexity of the natural world. 
Explanation: 
Multicellular organism such as human which is made of billions of cell. Each cell perform a specific function. The function of one organ is different from the other organ. For example, brain of human is made of millions of neurons which takes instructions from brain to the organs and bring messages from organs to the nervous system in the form of electrical impulses. In short every system in our body is full of complexity. 
 
        
             
        
        
        
Stars are classified based on the spectral type (i.e. a means to measure the photospheric temperature and density by getting information about the ionisation state).
Under the Morgan–Keenan (MK) system using the letters O, B, A, F, G, K, and M, a sequence from the hottest (O type) to the coolest (M type) (Harvard Spectral classification based on the surface temperature of the stars). A luminosity class is added to the spectral class using Roman numerals (Yerkes Spectral classification). This is based on the width of certain absorption lines in the star's spectrum (0 or Ia+ - hypergiants, I - supergiants, II - bright giants, III - regular giants, IV - sub-giants, V - main-sequence stars, sd - sub-dwarfs, and D - white dwarfs).
 
        
             
        
        
        
The Ethics of Using Human Embryonic Stem Cells in Research. Assume for the sake of argument that it is morally impermissible to destroy human embryos<span>. It does not follow that all research with HESCs is impermissible, as it is sometimes </span>permissible <span>to benefit from </span>moral<span> wrongs.</span>