Active muscles demand huge amounts of oxygen, and the circulatory system works hard to provide it. Blood carries oxygen to the muscles. When the body is at rest, blood carries nutrients to the muscles so that they can repair and rebuild themselves. Blood also carries away the waste products that hard-working muscles produce, back out through the lungs to be filtered.
so they Circulatory system xx muscular system :)
 
        
             
        
        
        
Answer:
chemical, mechanical, electrical 
Explanation:
 
        
             
        
        
        
Answer:
Eukaryotes have solved the end-replication problem by locating highly repeated DNA sequence at the end, or telomeres, of each linear chromosome.
Explanation:
Telomeres are stretches of DNA at the ends of the chromosome, They protect the genetic data and make it possible for cells to divide.
 
        
             
        
        
        
The Steady State Theory state that the density of the universe was remaining constant.
<h3>Steady State Theory:</h3>
In cosmology, a steady-state theory is a perspective that holds that the universe is constantly expanding while maintaining a constant average density. According to this theory, the matter is continuously created to form new stars and galaxies at the same rate that older ones fade away due to their expanding distance and accelerating recession. The average density and configuration of galaxies are the same as any location in a steady-state universe, which has no beginning or end in time. 
British scientists Sir Hermann Bondi, Thomas Gold, and Sir Fred Hoyle first proposed the hypothesis in 1948. Hoyle expanded on it in order to address issues that had come up in relation to the alternative big-bang theory. According to the hypothesis, in order to maintain a constant average density of matter across time, the new matter must constantly be created, primarily as hydrogen. With nearly five times as much dark matter, the amount needed is small and not immediately observable: one solar mass of baryons per cubic megaparsec every year, or one hydrogen atom per cubic meter every billion years.
Learn more about  steady-state here:
brainly.com/question/4956578
#SPJ1
 
        
             
        
        
        
Answer:
The correct answer will be option- synaptonemal complex.
Explanation:
The tetrad arrangement of the genetic material in an organism is mediated by a highly conserved structure known as the synaptonemal complex.  The synaptonemal complex is formed during the prophase I of the meiosis I which attaches the chromatin of the homologous chromosomes.
The synaptonemal complex is a proteinaceous structure which is formed by the two lateral ladders like elements with a central portion composed of the central element. The chromatin gets attached to the lateral elements while the central a portion bridge space between the two ladders thus help in the formation of the tetrad.
Thus, option- synaptonemal complex is the correct answer.