The geologic features that help scientists to determine the relative ages of rocks by their positions include index fossils, intrusions, and cross-cutting relationships (Option d).
<h3>What does geological age mean?</h3>
The expression geological age refers to the relative age of a given rock and or fossil (i.e. a piece or trace of dead organism) in a geological time scale.
In conclusion, the geologic features that help scientists to determine the relative ages of rocks by their positions include index fossils, intrusions, and cross-cutting relationships (Option d).
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Answer:
Symptoms
Signs and symptoms of hemophilia vary, depending on your level of clotting factors. If your clotting-factor level is mildly reduced, you may bleed only after surgery or trauma. If your deficiency is severe, you may experience spontaneous bleeding.
Signs and symptoms of spontaneous bleeding include:
- Unexplained and excessive bleeding from cuts or injuries, or after surgery or dental work
- Many large or deep bruises
- Unusual bleeding after vaccinations
- Pain, swelling or tightness in your joints
- Blood in your urine or stool
- Nosebleeds without a known cause
- In infants, unexplained irritability
Bleeding into the brain
A simple bump on the head can cause bleeding into the brain for some people who have severe hemophilia. This rarely happens, but it's one of the most serious complications that can occur. Signs and symptoms include:
- Painful, prolonged headache
- Repeated vomiting
- Sleepiness or lethargy
- Double vision
- Sudden weakness or clumsiness
- Convulsions or seizures
Causes
When you bleed, your body normally pools blood cells together to form a clot to stop the bleeding. The clotting process is encouraged by certain blood particles. Hemophilia occurs when you have a deficiency in one of these clotting factors.
There are several types of hemophilia, and most forms are inherited. However, about 30% of people with hemophilia have no family history of the disorder. In these people, an unexpected change occurs in one of the genes associated with hemophilia.
Acquired hemophilia is a rare variety of the condition that occurs when a person's immune system attacks clotting factors in the blood. It can be associated with:
- Pregnancy
- Autoimmune conditions
- Cancer
- Multiple sclerosis
Treatment
Several different types of clotting factors are associated with different varieties of hemophilia. The main treatment for severe hemophilia involves receiving replacement of the specific clotting factor that you need through a tube placed in a vein.
This replacement therapy can be given to combat a bleeding episode that's in progress. It can also be administered on a regular schedule at home to help prevent bleeding episodes. Some people receive continuous replacement therapy.
Replacement clotting factor can be made from donated blood. Similar products, called recombinant clotting factors, are manufactured in a laboratory and aren't made from human blood.
Other therapies may include:
- Desmopressin. In some forms of mild hemophilia, this hormone can stimulate your body to release more clotting factor. It can be injected slowly into a vein or provided as a nasal spray.
- Clot-preserving medications. These medications help prevent clots from breaking down.
- Fibrin sealants. These medications can be applied directly to wound sites to promote clotting and healing. Fibrin sealants are especially useful in dental therapy.
- Physical therapy. It can ease signs and symptoms if internal bleeding has damaged your joints. If internal bleeding has caused severe damage, you may need surgery.
- First aid for minor cuts. Using pressure and a bandage will generally take care of the bleeding. For small areas of bleeding beneath the skin, use an ice pack. Ice pops can be used to slow down minor bleeding in the mouth.
- Vaccinations. Although blood products are screened, it's still possible for people who rely on them to contract diseases. If you have hemophilia, consider receiving immunization against hepatitis A and B
Answer:
This means that the two separate rocks were once part of one piece of rock. These layers got separated most probably by continental drift as a result of tectonic plate movements. An example of such a fossil is the Mesosaurus, a freshwater crocodile-like reptile, that is found in Southern Africa and Eastern South America continents- that means they were once one land mass.
The environment in these two separate layers would most likely be different. As the layers drift apart from each other , they drift across latitudes that are determinants of climate in a region. Therefore, even the organisms in these two rock layers will evolve differently (even though they will share a common ancestor) in adaptation to respective environments – this is called allopatric speciation.
Answer - sea oats
Sea oats play a vital role in the development of sand dunes. The structure of their leaves and roots help in the trapping of the wind blown sand, promoting the growth of sand dunes and their stabilization. Sea oat plantation is encouraged in coastal areas to protect damage from heavy winds and high tide.
Answer:
Explanation:
Helium is the second most abundant element in the universe, but here on earth, it's rather rare. Most people guess that we extract helium from the air, but actually we dig it out of the ground. Helium can be found in certain parts of the world, notably in Texas, as a minor component in some sources of natural gas.
Helium is generated underground by the radioactive decay of heavy elements such as uranium and thorium. Part of the radiation from these elements consists of alpha particles, which form the nuclei of helium atoms. ... Helium can also be produced by liquefying air and separating the component gases
When the gas contains more than about 0.4% helium by volume, a cryogenic distillation method is often used in order to recover the helium content. Once the helium has been separated from the natural gas, it undergoes further refining to bring it to 99.99+% purity for commercial use.
