Idon't understand this!
nucleotide substitutions occur by mistake in a segment of ribosomal rna at a constant rate of one substitution every 10,000 years. a biologist has compared the ribosomal rna of two modern0day species and found that they have six differences in their sequences. how many years ago did these species diverge from a common ancestor? (2 points)
select one:
a. 3,000 years ago
b. 60,000 years ago
c. 30,000 years ago
d. 6,000 years ago

Option B, 60,000 years ago

Explanation:

It is given that the rate of substitution is one substitution per years

Thus, starting from the base year

Number of substitution after years

Number of substitution after years

Number of substitution after years

Number of substitution after years

Number of substitution after years

Number of substitution after years

Thus, it is clear that substitution or changes will occur in years.

Thus, option B is correct.

Puberty stage include different types of changes including cognitive (emotional), physical (voice, pubic hair, genitalia, etc.) and physiological (synthesis of sex steroid hormones) modifications

Explanation:

Physical puberty changes in girls occur from ages 10  to 14 and they are associated with the growth of pubic and underarm hair, breast development, and the first menstrual period (known as menarche). In boys, puberty occurs from ages 10 to 20, being this period associated with the growth of the testicles, the growth of pubic hair, changes in the voice, presence of sperms in the seminal fluid, etc.

Puberty hormones:  

     - Boys and girls: gonadotrophin-releasing hormone (GnRH) required for the production of Follicle Stimulating (FSH) and Luteinizing (LH) hormones

     -Boys: testosterone  

     -Girls: estrogen