Answer:
I think it's D, but it could be B.
Explanation:
Answer:
The nucleus, cell membrane and cytoplasm.
Explanation:
The nucleus, cell membrane and cytoplasm are three elements that cannot be absent in a cell because they are necessary for the survival of the cell. The nucleus controls and regulates the activities happening inside the cell e.g. growth and metabolism etc. Cell membrane acts as a wall to protect the inner part of the cell from the external environment as well as allows nutrients and gases inside and outside the cell. Cytoplasm serves as a medium for the conduction of nutrients and waste from on place to another and also for the medium for organelles in which they floats.
Answer:
Electron microscope would be used for if,
C) details of cell structures needed to be distinguished.
Explanation:
- The general principal of electron microscopy is analogous to light microscopy except that it uses electrons to analyse the specimen instead of light.
- Electron microscopy focuses a beam of electron on the target sample and records the difference in absorption by different surfaces.
- Electron microscopy is used to get the detailed structure of cells and surface features of various viruses and bacteria.
- However, it is not possible to view living biological samples through electron microscope because high velocity electron have immense energy to kill living cells.
- These samples are thus, fixed and then viewed.
Answer:
Planting trees, CARBON CYCLE, and cooking with gas do not add Carbon dioxide to the atmosphere.
Explanation:
The atmosphere naturally breathes or decomposes carbon dioxide rocks, whereas forest fire takes place and volcanoes erupt.
The atmosphere is naturally decomposed. Human activities like fossil fuel and forest burning, and cement production, also add carbon dioxide to the atmosphere.
Cancer is the result of unchecked cell division caused by a breakdown of the mechanisms that regulate the cell cycle. The loss of control begins with a change in the DNA sequence of a gene that codes for one of the regulatory molecules. Faulty instructions lead to a protein that does not function as it should
