Answer: Energy is passed up a food chain or web from lower to higher trophic levels. This loss of energy explains why there are rarely more than four trophic levels in a food chain or web. Sometimes there may be a fifth trophic level, but usually there's not enough energy left to support any additional levels.
Explanation: :) Hope it helps 
 
        
                    
             
        
        
        
Answer:
Bacteria and protists are unicellular organisms. The difference lies in the type of cells they have. Bacteria are placed in the kingdom Monera and have a prokaryotic cell, whereas protists are placed in the kingdom Protista and have a eukaryotic cell.
 
        
                    
             
        
        
        
Answer:
Because the gametes implemented in fertilisation are haploid in nature, in the case of humans, mature gametes contain 23 chromosomes instead of 46 which will then combine with another parents' 23 chromosomes during fertilisation, i.e: 23 (dad) + 23 (mom) = 46 (zygote)
Explanation:
A regular somatic cell has 46 chromosomes, 2n, 2 alleles but the gametes have 23 chromomes, n, 1 allele. The usual significance of this is so that there is diversity in the offspring and the offspring can gain characteristics (bad or good) from both parents.
 
        
             
        
        
        
It pulls towards it until it gets to a certain point and pushes away and so it stays in a steady orbit