Harmful or , is considered to be the source for new alleles and a main contributor to the diversity of life on earth. a) mitosis b) mutation c) transcription d) translation

Option B, Mutation

Explanation:

Genetic mutation causes diversity within the population of any species as it causes changes in genetic sequences.  The effect of such changes varies differently based on the point and time of their occurrence. Hence, mutation can be beneficial, non-beneficial and even neutral.  

Mostly these changes may be random or non-random in nature at the same time and even a single mutation can bring large effect. However, evolutionary changes are brought by accumulated effect of several mutations.  

Hence, option B is correct

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.