<span>Damming a river has a variety of effects on the freshwater ecosystem, more than just altering the flow from A to B. Dams create calm bodies of water, changing overall temperature regimes and sediment transport, leading to conditions which tend to favour generalist species. Loss of specialist species, particularly endemics, changes the community structure and leads to biotic homogenization. A dam will withhold sediment in the reservoir, not just decreasing the amount of substrate available to local freshwater species, but even impacting diadromous, estuarine and marine species much further downstream. The competition between resident species for food and breeding sites will increase as damming isolates populations, and perhaps more importantly, damming completely restricts migratory fish species. Isolation may lead to decreases in genetic diversity and therefore puts species at greater risk from disease. All of these effects may be exacerbated by changes in the surrounding land use. Overall, damming river flow will lead to both a loss of native species, but also an increase in exotic species which are more likely to become established in degraded habitats. For this reason, dams are one of the greatest global threats to freshwater biodiversity.</span>
Answer:
A- A pH change can cause the enzyme to change its shape
Explanation:
A rise or fall in the pH of the medium from the optimum of pH 7 usually affect the enzymes' active sites of and therefore the shape and the rate of enzyme activity.
Assuming the pH is too low, the enzyme medium becomes acidic;Acidosis. The high Hydrogen ions concentration interacts with the R-groups of the amino acids moiety of the enzymes, this interaction affects the ionization of the R-groups, disrupting the ionic bonding holding these R-groups in shape.
This results in loss of the 3-Dimensional shape arrangements of the protein molecule and therefore of the active sites. Since active sites of enzymes determines the specificity of the <u>enzymes substrate- complex </u> to give <u>enzyme-product complex,</u> the catalytic activity of the enzymes decreases, <u>the rate of reaction decreases,and products formation stops, and the reaction also stops.</u>
The same is applicable to extremely high pH=Alkalosis.
However, the effective buffer system of the body prevents this scenarios from happening in real sense in the body. Through mopping by the haemoglobin, excretion by the kidney, etc
Mitosis - 48 chromosomes (diploid cells)
Meiosis - 24 chromosomes (haploid cells)
Diploid cells. Meiosis is the process of cell division by which involving gametes. Cell division is just the same for sperm and egg cells, but they have distinguishable descriptions and labels in the process. Spermatogenesis is for the males’ sperm cells and oogenesis is the process for females’ egg cells. The cell division of meiosis involves the two phases, respectively meiosis I and meiosis II. Meiosis I like mitosis is the cell division that produces diploid cells<span>. These diploid cells are cells that contain a complete pair of chromosomes which is 46. The result is two diploid cells after the first meiosis. To provide clear explanation, in contrast haploid cells only contain 23 chromosomes and are created after meiosis II which is 4 in number.</span>
Answer:
B
(The result of DNA replication is two DNA molecules consisting of one new and one old chain of nucleotides. This is why DNA replication is described as semi-conservative, half of the chain is part of the original DNA molecule, half is brand new.)
Using Natural predators to reduce insect numbers caused the least harm to the environment.
