Environment, predators, and natural selection.
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Gram's staining is a differential staining technique that employs a primary stain like crystal violet and a counter stain like safranin along with the decolourizing agent alcohol and a mordant called the Gram's iodine.
Iodine is a mordant added after the primary stain. It fixes the stain by combining with it to enchance the staining ability. This forms an insoluble crystal violet iodine complex appearing purple under the microscope. These microorganisms are classified as Gram positive.
If addition of iodine is skipped, crystal violet is not fixed on the slide and the insoluble complex is not formed. The cells are decolourized by alcohol and are stained by the counter stain safranin making the Gram positive cells wrongly indentified as Gram negative due to its pink colouration. Thus, the slide will show all the cells as pink coloured Gram negative cells.
Answer:
Percentage of food eaten by the flock
Why is the percentage of food eaten a good number to use? Explanation:
A percentage compares the number of birds in the flock to the total number of birds in all flocks.
If the percentage is high, the flock is more successful, so the flock should grow.
If the percentage is low, the flock is struggling to eat, so the flock should shrink.
Answer:
B. Base pairing occurs within an RNA molecule to give RNA the three-dimensional shape needed for specific functions.
Explanation:
Ribonucleic acid, known as RNA, is a type of nucleic acid found in living systems. In opposition to the other type of nucleic acid (DNA), RNA is a short single stranded molecule. Both DNA and RNA are made of nucleotides, composed of a phosphate group, nitrogenous bases and a pentose sugar.
The presence of ribose sugar and Uracil base in RNA instead of deoxyribose sugar and thymine base respectively structurally differentiates the molecule from DNA. However, base pairing occurs within the RNA molecule to form the three-dimensional shape of the RNA, which is key to the specificity of its function.
