Answer:
the total entropy of an isolated system can never decrease over time.
Explanation:
The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. The total entropy of a system and its surroundings can remain constant in ideal cases where the system is in thermodynamic equilibrium, or is undergoing a (fictive) reversible process.
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Answer:
by the sarcoplasmic reticulum's calcium ion pumps
Explanation:
Rigor mortis or postmortem rigidity, is a state caused by chemical changes in the muscles that occur post mortem and cause the limbs of the corpse to stiffen.
This occurs because after death, there is no cellular respiration and consequently, no oxygen nor ATP (ATP is required for the muscle relaxation).
Calcium enters the cytosol after death because it is released due to the deterioration of the sarcoplasmic reticulum and due to the breakdown of the sarcolemma. Ca2+ ions activate the formation of actin-myosin cross-bridging necessary for the contraction. Muscles are unable to relax, because myosin heads continue to bind with the active sites of actin and there is no ATP to destabilize the myosin-actin bond.
Answer:
The leafhoppers eat plant tissues and, at the same time, they are eaten by spiders that are the food of large lizards. Finally, these lizards are the food of birds that are eaten by snakes.
Explanation:
The food chain starts with primary producers such as plants and algae (i.e., level 1), then goes through herbivorous species including insects and fish (level 2) and finally ends with carnivores such as rodents, snakes and hedgehogs (levels 3, 4 and sometimes 5, which depends on presence of larger predators). Thus, the trophic levels are represented by the number of steps of the food chain. In an ecosystem, the organisms can also be classified according to the mode of obtaining the food in producers (autotrophs), consumers (heterotrophs) and reducers (detritivores).
Answer:
1. Tar Roads: The qualities of Tar that makes it ideal for road construction are:
The tar-like material that is used for road construction is a combination (emulsion) of water and liquid asphalt. It serves the purpose of permeating and closing up small lacerations in the existing pavement.
When the emulsion sticks to the "gravel" it reduces the potential for vehicles to skid on the road thus enhancing safety. The "gravel-like" emulsion is applied by rolling and sweeping.
Qualities of Tar are:
- Adhesive: its the ability to stick to surfaces including materials such as gravel which it holds together makes it great for road construction;
- Waterproof: It is not water-soluble. Hence is not easily susceptible to the effects of running water.
- Resistant to High Temperature: The melting point of Tar is 54 degrees centigrade. The ground can heat up to 45 degrees celsius thus making Tar perfect for road construction as it can remain rigid even in the worst temperatures.
2. Iron Burglar Bars
Steel bars are made from iron. The qualities of steel which make it perfect for securing places and things are:
- Strength; This is the ability to withstand breakage and or destruction.
- Toughness: Steel is very tough and can not easily bend or break under static loads.
- Weldability: Most steel bars are actually welded together. Without this ability, steel probably would be useless as a material that can be used for protection
- Durability: The only factor that degrades steel is rust. Rust happens when steel is exposed to oxygen which can be found in air and water.
3.) Plastic Furniture
The primary qualities of plastic that make them suitable for furniture are:
- Chemical stability: It does not rust or degrade when exposed to weather elements such as oxygen, water, etc.
- Good impact resistance: Depending on its thickness, plastic can bear a lot of weight and can take a lot of impact without deforming or breaking
- Good transparency and wear resistance: Plastic can be made transparent. This quality is essential for aesthetic purposes and hence can be used for various kinds of good-looking furniture. As furniture, its surface does not come off like hence it's durability.
- Low thermal conductivity: This means that it can bear heat without transmitting it easily.
- Ability to General formability, good coloring, low processing cost.
4) Metal Jewellery
One of the best metals for jewelery is Tungsten. This is so because it is more durable and stronger than any other kind of material that can be used for jewelery purposes. It is about ten times harder than 18K gold and about four times harder than titanium. Other materials that can be used are:
- titanium
- stainless steel and
- cobalt
5) Clay
In it's raw form, clay used for building might not be the best idea as it susceptible to water absorption and hence deformation which generally leads to a collapse of the structure. However, it becomes an excellent material of choice after it has been hardened into brick.
Brick is preferred in construction due to the following qualities:
- hardness
- High Compressive strength,
- Low Water Absorption
- Frost resistance
- Fireproof
- Great Insulation
6) Cotton is usually preferred as the material of choice for most kinds of clothing due to the following qualities:
- Softness. The cotton plant is soft and fluffy and results in a fabric often retains that soft feel.
- Durability: Its molecular structure makes it able to last very long.
- Absorbency: it is able to absorb moisture/water. Hence making it more comfortable than synthetic materials
- High Dye Tolerance: Ability to hold dye well is an indespensable quality of a good fabric. You don't want to have a fabric whose colours are quick to fade.
- Breathability: This reduces is very important especially during summer or when the weather or environment is very hot.
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Answer:
This is an controlled experiment because he is only changing the amount of carbon dioxide in the air. Since he is only changing one variable at a time and comparing it to a natural, unaltered tomatoe area, his experiment is controlled.
Explanation:
The definition of a controlled experiment is a test where the person conducting the test only changes one variable at a time in order to isolate the results. An experiment where all subjects involved in the experiment are treated exactly the same except for one deviation is an example of a control experiment.