Answer:
Structures that are still present but currently serve little to no purpose
Explanation:
<em>Vestigial structures/organs are general defined as structures/organs that are present but poorly developed without any functional use in the present living organisms but thought to have been fully developed and functional in their ancestors.</em>
Fully developed and functional organs gradually become less developed and non-functional across generations as the environment keeps changing and organisms found lesser use for the organs. An example includes the <u>caudal vertebrae</u> found in man which is kind of useless but thought to have been fully developed and functional in the ancestors of man - the monkeys.
<u>Vestigial organs are often used as one of the morphological evidence of the evolution of living organisms.</u>
 
        
             
        
        
        
Switch A and D, but other than that your answers are correct. 
An astronomical body is an object in space.
A comet is a celestial object consisting of a nucleus of ice and a stream of gas and dust. 
A moon is an astronomical body that orbits around a planet. 
A galaxy is a system of start held by gravitational attraction.
 
        
             
        
        
        
The answer is dominant.
A monohybrid cross involves organisms that are heterozygous for only one character. In autosomal dominant traits, the phenotype is present if both copies of the dominant allele (A) are present (homozygous individuals AA) or only one copy of the dominant allele is present (heterozygous individuals Aa). <u>Thus, t</u><span><u>he characteristic that results from a monohybrid cross is the dominant trait.</u></span>