(A nebula)
is a cloud of gas (hydrogen) and dust in space. Nebulae are the birthplace biths. There are different types of nebula. An Emission Nebubla such as Orion nebula, glows brightly because the gas in it is energised by the stars that have already formed within it.
(A star)
is a luminous globe of gas producing its own heat and light by nuclear reactions (nuclear fusion). They are born from nebulae and consist mostly of hydrogen and helium gas.
(red giant)
This is a large bright star with a cool surface. It is formed during the later stages of the evolution of a star like the Sun, as it runs
out of hydrogen fuel at its centre.
(red dwarf)
These are very cool, faint and small stars, approximately one tenth the mass and diameter of the Sun. They burn very slowly and have estimated lifetimes of 100 billion years.
(white dwarf)
This is very small, hot star, the last stage in the life cycle of a star like the Sun. White dwarfs have a mass similar to that of the Sun, but only 1% of the Sun's diameter; approximately the diameter of the Earth.
(Black holes)
are believed to form from massive stars at the end of their life times. The gravitational pull in a black hole is so great that nothing can escape from it, not even light. The density of matter in a black hole cannot be measured.
Answer:
The correct answer is: C.
Explanation:
- The given situation is the example of a Reflex Action.
- Reflex action can be defined as an action shown in response to a sudden stimulus.
- The CNS or the Central Nervous System is comprised of the Brain and the Spinal Cord which receives the Sensory impulses from the Receptor organ, integrates or decides on the response which needs to be provided and then sends the Response impulses to the Effector organ.
- The PNS or the Peripheral Nervous System is comprised of the sensory and motor neurons those are responsible for connecting the Sensory organ and the Motor organ to the CNS, respectively.
- In the situation, Sarah's eyes perceives the ball and sends sensory impulses through the optic nerve containing the sensory neurons (PNS) to the spinal cord.
- The spinal cord possess inter-neurons (CNS) that decides over the action to be done in response to the stimulus.
- The Response stimulus is send from the inter-neurons via the motor neurons (PNS) to the eye muscles of Sarah and Sarah performs the action, that is, she blinks.
Answer:
If a person has a diet high in saturated fats, LDL cholesterol molecules can carry cholesterol from the liver to cells and to the arterial walls whereas HDL cholesterol transports cholesterol from the cells to the liver where it is converted to bile salts which can modulate cardiovascular function.
Explanation:
Cholesterol is a lipid generated in the liver that is used to make hormones and vitamin D, but can also be ingested when eating fats.
Cholesterol can be divided into two types: LDL (low-density lipoprotein) and HDL (high-density lipoprotein).
LDL is commonly known as the "bad cholesterol" and is responsible for the deposit of cholesterol in the walls of arteries, which generates atherosclerosis and can potentially lead to strokes or heart attacks because it occludes the vessels and makes it impossible for the blood to advance.
HDL is also called "good cholesterol" because it takes the cholesterol from the cells to the liver where it'll serve a good cause, instead of blocking the arteries.
To reduce the amount of LDL, it's best to limit the consumption of fatty meats, dairy products and other saturated fats. Foods with a good amount of HDL are those with unsaturated fats, like fish, nuts and seeds.
Answer:
Seaweed might start to grow out of control withough crabs eating it, octopuses on the other hand would struggle to find food and start to die off because they relie on crabs to be their food source.
The United States is the world's biggest oil consumer, followed by China, Japan and India.
