The Vestigial Structures are those whose original function was lost during evolution. In humans, these structures are the appendix, the coccyx, the wisdom teeth and others. In animals, examples of vestigial structures are the wings of flightless birds, hind leg bones on whales and pythons and eyes in blind fishes. Those vestigial structures help scientists study the evolution of some species.
The correct answer is color vision. The macula lutea is an area near the center of the human's eye retina. It has an oval shape and is responsible for the high-resolution color vision we have under good light conditions. If the macula lutea is destroyed, due to macular degeneration or a retinal detachment, then this color vision is impaired.
Gram staining is a technique of separation of the bacteria based on the cell wall composition. Steps involved in gram staining are:
1) Primary stain application which is known as crystal voilet, it stains all cells purple/blue.
2) Mordant stain application which is known as iodine solution, is added, and form crystal iodine complex, all cells continue to stain blue/purple.
3) Decoloration step, in this step, we can differentiate gram negative or gram positive bacteria. So, decolorizing agent such as ethanol or acetone extracts blue color from thin walled peptidoglycan layer gram negative bacteria, and gram positive bacteria remain blue/purple because it contains thick walled peptidoglycan layer.
4) Counterstain application in this step safranin red dye stain the gram negative decolorized cells red/pink, and gram positive bacteria remain same blue.
So, if a student is performing a Gram stain of a mixed culture of both E. coli and S. aureus, and he forgets to decolorize with ethanol Both the bacteria should appear blue/purple color.
If the father has hemophilia and the mother DOESN'T the daughters any will have and the sons won't. If the moms have it and the dad doesn't that means all of the sons will have it and the daughters won't