Answer:
The functional groups that define the two different ends of a single strand of nucleic acids are:
B. a free hydroxyl group on the 5' carbon a free hydroxyl group on the 3' carbon
G. a free phosphate group on the 5' carbon
Explanation:
A nucleic acid is a polymer formed of nucleotides that are linked with a phosphodiester bond. The structure of a nucleotide consists on a phosphate group linked to a pentose (ribose in RNA and deoxyribose in DNA) that is also attached to a nitrogenous base. The nitrogenous bases are adenine, guanine, cytosine, thymine (in DNA) and uracil (in RNA).
DNA and RNA are nucleic acids which can be found in a double or single strand presentation.
Nucleic acids are synthesize in the 5’ to 3’ direction, so that is why the convention is that the sequences are written and read in that direction.
The strand of a nucleic acid is directional with an end-to-end orientation, where the 5’ end has a free hydroxyl or phosphate group on the 5' carbon of the terminal pentose, and the 3’ end has a free hydroxyl group on the 3’ carbon on the terminal pentose (ribose/ deoxyribose).
Answer: The correct answer is -
D) giraffes having increasingly longer necks over time.
Natural selection is an evolutionary mechanism that was proposed by Darwin.
According to this mechanism, organisms that are better capable of adapting to their changing environmental conditions, survive and increase their number through reproduction whereas other are eliminated from the population.
Example - Long neck of Giraffe, which is much elongated, lofty stature, that was beautifully adapted for browsing on the higher tree branches. This was an adaptation with slow and gradual change in the gene frequency as the lower vegetation was eaten by other animals. Due to this, giraffes had to search for other source (that was higher tree branches).
This is considered as a peculiar example of natural selection.
Agriculture= Crops that are disease resistant, stay fresh longer, insect resistant and higher number of crops
