Answer:
False
Explanation:
Beryllium is used in alloys with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes and non-sparking tools. Mixing beryllium with these metals increases their electrical and thermal conductivity. Other beryllium alloys are used as structural materials for high-speed aircraft, missiles, spacecraft and communication satellites. Beryllium is also used in nuclear reactors as a reflector or moderator of neutrons.
<span>The minimal amount of nutrients needed every day by healthy people to prevent nutrient deficiencies is called the RDA.
RDA stands for recommended dietary allowances. </span>RDA's are established by the Food and
Nutrition Board of the National Academy of Sciences. There is a term RDI related to this. RDI stands for recommended daily intake.
The correct answer is: A. The hydrophilic head groups of the lipid molecules are exposed to the outside of the cell and the cytoplasm, which is a water-like environment. The hydrophobic tails form an oily layer inside the membrane that keeps water out of the cell.
Plasma membrane of the cell is arranged in a bilayer of phospholipids. Phospholipids are amphipathic molecules which means that they have both hydrophilic and hydrophobic regions. The hydrophilic heads of phospholipids that are faced outward and hydrophobic layer located in the interior of the bilayer together make a good barrier between the interior and exterior of the cell, so the water and other polar or charged substances cannot easily cross the hydrophobic core of the membrane.
Answer:
Natural selection. It is simply the process by which random variations that give an individual a favorable adaptation to its environment survive to be passed on to offspring.
