Answer:
Explanation:
Staining is done for onion cells to visualize the cytoplasm of yellow and white onions because they are not pigmented. The staining of human cheek cells with methylene blue is necessary to stain the nucleus to get clear image of it under microscope because methylene blue binds to negative charge nucleic acids
While for leaf epidermal cells smears, staining is not necessary as they are visible under light microscope without staining and they also have pigmented materials inside them such as chlorophyll chloroplast. The cork cell is a non-living and have a cell wall whose structure is visible under light microscope.
Answer:
Nucleus (as nuclear DNA),mitochondrial(mitochondrial DNA) and chloroplasts.
DNA is packed tightly around protein called Histones, in Eukaryotes cells;so that many molecules can easily be held together as chromosomes.
Chromosomes are thread-like structure in nucleus of cells.The histones provide support to the DNA molecule
The part DNA molecule coded for by a polypeptide is GENE, therefore in the nucleus of cells, DNA contains GENE,and the gene and DNA are packed in chromosomes,DNA appears as circular DNA mitochondria
Explanation:
Answer:
The cell membrane is semi-permeable. It allows some molecules to enter easily inside the cell whereas some molecules are blocked from entering the cell.
Small, polar molecules and hydrophobic molecules enter easily through the cell membrane. But large molecules and ions cannot easily move inside the cell membrane.
A hydrophilic substance like the substance L mentioned in the question enters the cell membrane through the help of carrier proteins. The substance attached to the large protein might enter through active or passive diffusion but it can only enter the cell by attaching to carrier proteins.
The light-dependent reaction<span> takes place on the thylakoid membranes</span>
Answer:
I think the answer is C
''Reusing plastic bags''
Explanation:
Removing carnivores from a forest has a great impact on a environment since the population of the herbivores will increases drastically and the dynamic equilibrium of the area will be greatly effected.
If we look at choice B '' Heating homes with fossil fuels'', this will also have a big impact on the earth since fossil fuels are non-renewable and take centuries to form. Heating homes with them will result in loss of fossil fuels.
Now let's look at choice D ''Adding heavy metals to the water supply''. Heavy metals are dangerous to the human health and even cause cancer. This will cause thousands of deaths and will also have a great impact on the global stability.
This leaves choice C ''Reusing plastic bags''. This will cause less pollution and less harm to wildlife but doesn't have any big threat to the global stability. As in changing the world population or causing deaths in large numbers.
so I think choice C is the answer
