<span>A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation.</span>
Answer:
Metaphase
Explanation:
The metaphase stage of the cell cycle precedes the anaphase and the telophase stages. During this stage, the metaphase plate is formed and chromosomes align along this plate which also represents the equator of the cell.
After lining up, mitotic spindles attach to each chromosome at the centromere. Shortening of the spindles results in separation of sister chromatids of the same chromosome and their eventual migration to the opposite poles of the cell.
<em>Hence, if the mitotic spindle refuses to attach to chromosomes, cells would most likely be arrested in the metaphase stage and will never be able to proceed beyond it.</em>
Answer;
-All of the above
-pathogens, disease vectors, and high levels of contaminants
Explanation;
Water pollution is a large set of adverse effects upon water bodies (lakes, rivers, oceans, groundwater) caused by human activities. Water pollution is caused by;
- Increases in nutrient loading may lead to eutrophication.
-
Organic wastes such as sewage and farm waste impose high oxygen demands on the receiving water leading to oxygen depletion with potentially severe impacts on the whole eco-system.
- Industries discharge a variety of pollutants in their wastewater including heavy metals, organic toxins, oils, nutrients, and solids.
- Discharges can also have thermal effects, especially those from power stations, and these too reduce the available oxygen.
The significance of the eye spot of the Euglena cells is a
light receptor.
The light receptor allows the light to enter and orient the
cell to move towards the light or to move away. The eye spot is also known as
the stigma.
<span />
