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 correct answer is option a.
Explanation:
Prezygotic isolation is a mechanism by which mating and fertilization is prevented. Thus, it prevents the formation of a zygote.
It can be achieved by various reasons such as temporal differences (difference in mating seasons), habitat isolation, behavioural differences (different mating rituals such as different dance patterns, voice calls, et cetera), mechanical isolation, et cetera.
Thus, different breeding calls prevent the species to interbreed with each which ultimately prevent the formation of zygote formation.
Hence, it is a type of prezygotic isolation.
Given:
Allele for green pod colour = Gg (Heterozygous)
Allele for Yellow pod colour = gg (Homozygous)
Explanation:
Parents: Gg x gg
When this two parent are crossed, it leads to the following F1 generation (off springs):
<em>• Gg (green colour pod)
</em>
<em>• Gg (Green colour pod)
</em>
<em>• gg (Yellow colour pod)
</em>
<em>• gg (Yellow colour pod)
</em>
Form the produced offspring it can be inferred that the allele combination for green colour pod is Gg. Among the four off springs obtained 2/4 are green colour pod and 2/4 are yellow colour pod.
Answer:
While Americans constitute the 5% of the world population, they use around the 24% of the world's energy.
Then, if the 100% of the population were like the Americans, we have:
5%*x = 100%
x = 100%/5% = 20
the whole population is 20 times the population of the US, then the total energy used is 20 times the energy used in the US.
Then the energy that the 100% of the population would use is equal to:
20*24% = 480%
Sowe actually would need like 5 Earths.
So none of the options is matches this, but this may be because this question is about some specific resources and not for the specific energy used. The closest option is 200%
