Answer: Place a pattern in sand to create a mold.
Incorporate the pattern and sand in a gating system.
Remove the pattern.
Fill the mold cavity with molten metal.
Allow the metal to cool.
Break away the sand mold and remove the casting.
Explanation:
The part of the peripheral nervous system (PNS) neuroglia that form the myelin sheaths around larger nerve fibers in the PNS would be the Schwann cells. The most important function is to myelinate the axons found in the PNS. Myelin aids in the increase of the saltatory conduction of a neuron.
Answer:
Evolution means change in the physical features of an organism.
Explanation:
Evolution means change in the physical features of an organism. Evolution occurs in the population of an organisms due to various factors such as mutation, non-random mating and natural selection. Nonrandom mating occurs when an organism prefer mating with particular superior organisms or with the similar organism. Mutation in the genetic makeup of an organism is also responsible evolution. this mutation occurs when an organism experience ultraviolet radiation from the sun, or also occur if an error in DNA during cell division. Gene flow is also known as gene migration is the transfer of genetic material or traits from one population to another when the organism is migrated to another environment. Some organisms are selected naturally because they have the potential to survive in that environment so they survive and that doesn't adopt itself to the environment, it will extinct from the environment.
Answer:
When a pathogens cross non-specific barriers (skin) they disturb the homeostasis of the body. however inside body they are confronted by different types of white blood cells which are responsible for bringing homeostasis again in the body. these are described below.
Role of macrophages in maintaining homeostasis
Macrophages are white blood cells (phagocytes) constantly patrolling in the body and destroy other cells by engulfing and ingesting them through the process of phagocytosis. These are produced in bone marrow cells as monocytes which have short life of only 10-20 hours. Once monocytes leave the blood they become macrophages. From bone marrow to the blood, macrophages are transported to the area of the body where they are needed. Macrophages engulf the whole body, after digesting particles (bacteria) can extrude the residual particles. Thus, provide protection by trapping and destroying microorganisms entering the tissue. They also secrete different proteins. Some of these proteins trigger the maturation of monocytes into macrophages, thereby increasing their numbers. Another protein interleukin-1 signals the brain to raise the body temperature, producing fever. The higher temperature aids the immune response and inhibit the growth of invading microorganisms.
Role of natural killer cells in maintaining homeostasis
They are another class of white blood cells that don’t directly attack invading microbes. Instead they strike at the body’s own cells that have been invaded by viruses. Virus infected proteins bear viral proteins on their surfaces. Natural killer cells recognize and kill cancerous cells. They secrete proteins into plasma membrane of the infected or cancerous cells. They also secrete enzymes that break up some of the molecules of the target cells, as a result the target cell soon dies.
The correct order is:
B. Rain water is stored in rock and seeps into a hairline crack during a rainfall;
E. The temperature falls below 0° Celsius;
D. Rainwater in the rock crack freezes into ice;
C. Because ice occupies more space than water, the ice wedges the crack open:
A. The freeze-thaw cycle continues to deepen the crack until the rock splits into 2 pieces;
The water from the rain gradually manages to weather parts of the rock. As it does, small cracks appear in it. Once there's cracks, the water from the rainfall also starts to store inside the rock. When the colder period of the year comes, and the temperatures fall bellow 0°C, the stored water freezes. The ice starts to spread inside the crack, thus creating pressure inside the rock. As the pressure is becoming bigger and bigger, the rock will eventually crack into two or more pieces.
