Answer:
Because older cultures of gram-positive bacteria tend to lose their ability to retain crystal-violet in the peptidoglycan of their cell walls and can be confused with gram-negative bacteria.
Explanation:
Gram staining is used to differentiate between two major groups of bacteria. Gram-positive and gram-negative, these bacteria differ in the amount of peptidoglycan in their cell walls. Gram-positive bacteria have a higher amount of peptidoglycan, which absorbs the violet crystal complex used in gram staining, staining them purple/violet. Old cultures of gram-positive bacteria tend to lose the ability to retain the violet crystal and are stained by safranine, staining them red/pink and appear to be gram-negative.
<span>The inability to recall which numbers on a telephone dial are not accompanied by letters</span>
<span>1.
</span>Cones perceive
light in color while rods perceive light in black and white.
<span>2.
</span>Rods can perceive dim light, unlike cones. The rods are located at the edges of the eyes. This is why it easier to perceive an image in the dark through
the corner of the eyes.
<span>3.
</span>The discs that compose the cones are usually
partially open to the surrounding vitreous
fluid while those of the rods are closed.
Answer:
Desertification is the destruction of the biological potential of the land and it is generally viewed as an advanced stage of land degradation. human activities also cause the process such as poor irrigation practices, deforestation, the expansion and intensive use of agricultural lands, and overgrazing.
Such human activities put enormous pressure on the land by altering its soil chemistry and hydrology. Modern agriculture causing a negative impact on the soil and land by overexploiting the biological and chemical potential of the land.
