<span>They are composed of similar materials: DNA is a deoxyribonucleotide polymer while RNA is a ribonucleotide polymer. A nucleotide is composed of a nitrogenous base, a sugar, and a phosphate group. In ribonucleotides, the sugar is ribose, while in deoxynucleotides, the sugar is deoxyribose. Adenine, guanine, and cytosine are nitrogenous bases in both DNA and RNA, while thymine is found only in DNA and uracil is found only in RNA.</span>
One big place and they will one big population
Answer:
The correct order is dehydration, embed in wax, cut into sections, staining
Explanation:
There are certain proceedings needed to obtain stained sections of vegetable or animal tissues for their microscope observations.
These steps are:
- Obtention of the material: The tissue is cut to an adequate size.
- Fixation: When tissues are extracted from the organism, they suffer autolysis and putrefaction, so they need to be fixated in order to keep their cells in the best state possible. Fixation involves preserving the original morphological and molecular characteristics of the tissue. Fixation avoids autolysis, putrefaction, distortion, and retraction of cells and the tissue that could affect its volume or morphology.
- Dehydration. Once fixated, the fixator must be eliminated and the tissue is dehydrated by using a gradual series of solutions with alcohol in ascendant concentrations. Dehydration must be gradual to avoid tissue deformation.
- Inclusion. To obtain thin cuts that can be observed under the optic microscope, the tissues must be included in a consistent, firm substance, that might be either hydrophilic or hydrophobic. A hydrophobic medium is paraffin wax, that provides hardness and plasticity.
- Cut. The tissue included in wax must be cut in slides or sections thin enough to allow the diffusion and penetration of light. A microtome is used to perform these cuts. When using paraffine for tissue inclusion, the cuts are about 5 to 20 micrometers of thickness.
- Stain. Once the cuts are performed, paraffin wax must be eliminated. This can be done by using an organic solvent. Then the tissue must be stained. Hematoxylin and Eosin are the most common dyes. Animal tissues in general do not have any natural color, so they need to be stained to be observed.
Answer:
The Laura tried to grow micro-organisms in culture broth medium in Petri-plates but the microbial growth was not observed even on the fourth day of culture which could be due to:
1. Laura could have not provided the correct broth medium maintaining the with pH and salt concentrations.
2. Microorganisms did not get optimal growth conditions.
3. The bacterial source could have died after the collection which could have lysed after their death and thus no longer visible.
Answer:
easy to produce, affordable, abundant
Explanation:
A non-renewable resource is defined as the natural resources which are not ereadily replaced through natural means and it takes thousands of years for their renewal. Example of non-renewable resource include Fossil fuels such as natural gas, oil and coal.
<u>There are many advantages of non-renewable resources such as:</u>
1) Easy to produce: non-renewable resources are easy to produce because processing stations can be easily developed for refinement and distillation of non-renewable resources.
2) Affordable and abundant: non-renewable resources are affordable and abundant in the earth. for example diesel and oil are good choices for powering vehicles.
Hence, the correct options are easy to produce, affordable, abundant.
