Question:All known organisms use genetic information to produce protein molecules via the same genetic code. This finding strongly supports the hypothesis that __________.
a) the earliest macromolecules probably arose when lightning struck an oxygen-free atmosphere
b) all organisms are descended from one or a few common ancestors
c) the genetic code readily evolves by natural selection
d) there's only one possible way to encode information in a macromolecule
Answer:
b) all organisms are descended from one or a few common ancestors
Explanation:
Protein synthesis occurs when the nucleotide sequence of the mRNA is read in the form of genetic codes. A specific genetic code specifies the same amino acid in all living beings. For example, the code "UUU" codes for phenylalanine in all the living beings irrespective of their species. This suggests that all the life forms have originated from one or few common ancestors and the genetic code has been preserved during the course of evolution of various species.
Distribution of phenotypes within a population may be impacted by different types of natural selection. These types of selection include;
Directional selection involves a change in the environment shifts of phenotypes observed. Example is the giraffe neck-length, where the length got longer and longer over time to reach the leaves at the top of trees.
Stabilizing selection , this is a selection where an average phenotype is favored. example is number of eggs laid by birds such that too many eggs will be a waste of energy because some chicks would starve.
Disruptive selection is a selection where individuals with an average value of a trait are affected most while those with values below average are affected least. Example small individuals are capable of hiding from predators while big individuals can not fit in the hiding place but instead will fight with predators.
This means that a single carbon atom can form up to tetravalent bonds with other atoms
The highest between 25 and 50;the lowest between 55 and 74
