Answer:
<em>The correct option is C) Continental shelves</em>
Explanation:
The continental shelf can be described as a part of a continent which is submerged in shallow water. This shallow water is known as a shelf. Hence, the name continental shelves.
Rich deposits of oil and natural gas can be present in this part of the sea. The continental shelves are of extreme commercial significance and are a commercial site for exploitation. The continental shelves can be rich in metallic and non- metallic ores and hydrocarbon products.
Fuel cells can make an electricity from a simple electrochemical
reaction in which oxygen and hydrogen combine to form water. There are several
different types of fuel cell but they are all based around a central design
which consists of two electrodes, a negative anode and a positive cathode.
These are separated by a solid or liquid electrolyte that carries electrically
charged particles between the two electrodes. A catalyst, such as platinum, is
often used to speed up the reactions at the electrodes. Fuel cells are
classified according to the nature of the electrolyte. Every type needs
particular materials and fuels and is suitable for any applications. The
article below uses the proton exchange membrane fuel cell to illustrate the
science and technology behind the fuel cell concept but the characteristics and
applications of the other main designs are also discussed. Proton Exchange Membrane Fuel Cells (PEMFC)
The hydrogen ions permeate across the electrolyte to the
cathode, while the electrons flow through an external circuit and provide
power. Oxygen, in the form of air, is supplied to the cathode and this combines
with the electrons and the hydrogen ions to produce water. These reactions at
the electrodes are as follows:
Anode: 2H24H+ + 4e-
Cathode: O2 + 4H+ + 4e- 2H2O
Overall: 2H2 + O22H2O + energy
PEM cells operate at a temperature of around 80°C. At this
low temperature the electrochemical reactions would normally occur very slowly
so they are catalysed by a thin layer of platinum on each electrode.
Answer:
Explanation:
The bloodstream carries glucose-a type of sugar produced from the digestion of carbohydrates and other foods-to provide energy to cells throughout the body. Unused glucose is stored mainly in the liver as glycogen.
Insulin , glucagon, and other hormone levels rise and fall to keep blood sugar in a normal range. Too little or too much of these hormones can cause blood sugar levels to fall too low (hypoglycemia) or rise too high (hyperglycemia).
Normally, blood glucose levels increase after you eat a meal. When blood sugar rises, cells in the pancreas release insulin, causing the body to absorb glucose from the blood and lowering the blood sugar level to normal. When blood sugar drops too low, the level of insulin declines and other cells in the pancreas release glucagon, which causes the liver to turn stored glycogen back into glucose and release it into the blood. This brings blood sugar levels back up to normal
Options for part A are as follows:
A) A mutation in the operator sequence
B) A mutation in the lac-Z gene
C) A mutation in the lac-Y gene
D) A super repressor mutation
Answer:
The correct answer:
Part a - A mutation in the operator sequence
Part b - It ensures that a cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment
Part C. true.
Explanation:
part a:
If there is a mutation in the operator sequence leads to prevent binding of the repressor which leads to allowing constitutive expression of the genes various conditions.
part b:
The biological role of the lac operon makes sure that the cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment
Part c:
RNA polymerase cannot transcribe the structural genes due to the repressor binds to the lac operator, therefore, the proper function of the lac operon is possible when the placement of the operator sequence between the promotor and the structural genes.
