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.
In the dark, an object is more clearly seen when viewed in peripheral vision than when viewed directly, this phenomenon occurs because the rods located in the retina are:<u> more </u><u>sensitive</u><u> in the dark than </u><u>cones</u>.
The retina extends through the posterior portion of the eyeball is the innermost layer and in it are the photoreceptors: cones and rods.
Rods and cones are the two types of photoreceptor cells in vertebrates that capture light energy (photons) and convert it into electrical signals.
- The rods are sensitive to changes in light, since their detection thresholds are low, so they only come into operation when the light intensity is low (scotopic vision or night vision).
- Scotopic vision has relatively low acuity, as the details of an object cannot be discerned or its color appreciated.
- On the contrary, cones have a much higher threshold for light, they are responsible for daytime vision (photopic vision) and their mission is to detect colors and shapes (details).
Therefore, we can conclude that in the dark, an object is more clearly seen when viewed in peripheral vision than when viewed directly, this phenomenon occurs because the rods located in the retina are: more sensitive in the dark.
Learn more here: brainly.com/question/14018797
Answer:
A. 1' ... 5'
Explanation:
The pentose sugars present in nucleotides have five-carbon structures. Other components of a nucleotide are a phosphate group and a nitrogenous base. The nitrogenous base in a nucleotide can be a purine or pyrimidine. The purine bases are covalently joined to the 1' carbon atom of the pentose sugar at their N-9. The bond between the nitrogenous base and a pentose sugar is called the N-beta glycosyl bond.
Similarly, N-1 of a pyrimidine base is covalently linked to the 1' carbon of the pentose sugar. The phosphate group of a nucleotide is bonded to the 5' carbon of the pentose sugar.
The Answer gotta be C or D
The PAX-6 gene is a gene that translates to the PAX-6 protein that serves as a transcription factor needed to activate certain genes that functions in the development of the eyes. While PAX-6 gene may look like it produces different functions for different species (such as formation of the compound eye in insects vs. formation of a single lens eye in vertebrates), it does not. It does in fact only regulate the genes required for the formation of the eyes. Absence or mutation of the PAX-6 gene will cause aniridia or absence of the iris, opaque lens and cornea, and a dysfunctional retina. Also, the function of the PAX-6 protein is conserved throughout evolution of species.
