Answer:
i) Rusting occurs the least in tubes 2 and 3 because either of air and water which are necessary for rusting is absent in the two tubes respectively.
ii) Rusting occurs most in tube 1 because both air and water which are necessary for rusting are present.
Explanation:
Rusting is a chemical change which involves a redox reaction. During the process of rusting, metallic iron is oxidized to hydrated iron (iii) oxide by oxygen present in air.
For rusting to take place effectively, each of these three factors mist be available: metallic iron, oxygen and water.
In the figure above, the iron nails in the three tester tubes will rust to different extents based on the availability of the three factors.
In test tube 1, the iron nails will rust the most because all the three factors: metallic iron, oxygen present in air, and water are abundantly present.
In test tube 2, the iron nails will rust the least or not at all because boiling of water removes dissolved oxygen from water and the oil layer above the boiled water prevents entry of oxygen from air. Thus, the nail do not rust because one of the three factors for rusting to take place, in this instance, oxygen is absent.
In test tube 3, the iron nails rusts the least or not at all as well because moisture or water is absent. Calcium chloride, a drying agent removes all the moisture from inside the tube. Hence, even though air is present, rusting do not occur as there is no moisture or water present.
A. Neutral water
Less than 7 is acidic (which has 6 letters, 6< 7)
More than 7 is alkaline (which has more than 7 letters). Alkaline = basic
7 is neutral
The signal transduction pathways<span> recruited by the receptors of these hormones and growth factors </span>are<span> of particular interest.
Im not too sure about this might wanna check it.</span>
Unicellular organism ...................................................................................................
Answer:
- Fresh water fish have higher salt contents in their bodies than in their environments.
- Marine fishes have less salt in their bodies than their environment
- Terrestrial organisms have the challenge of water retention due to atmospheric contact.
Explanation:
FRESH WATER OSMOREGULATION
The salt concentration in salt water fish is higher than the concentration found in its environment (fresh water). This causes water to enter into the body of the fish through osmosis and without regulating processes, the fish is bound to swell and likely burst.To compensate for this challenge, the kidney in fresh water fish produces a large amount of urine, causing them to lose salt. To ensure too salt is not lost beyond the basic requirement, chloride cells in the gills take up ions from the water which are transported into the blood.
MARINE OSMOREGULATION
In marine fishes, the challenge opposes that of fresh water fishes since salt content in this case is lower in their blood than in their environment. To address this challenge, marine fishes lose water constantly while retaining salts to lead to a build up. The water lost, is then made up for and replenished by continual drinking of seawater. The chloride cells in marine fishes works in a manner opposing that of fresh water fish, functioning to compliment the excretion of salts by the kidney.
TERRESTRIAL OSMOREGULATION
The major challenge of osmoregulation in terrestrial organisms is water regulation in the body owing to their contact with the atmosphere.
Terrestrial organisms possess effective kidneys which enable osmoregulation. A series of processes including filtration, re-absorption and tubular secretion, enable regulation of fluids and water conservation.
Water passes out of the descending limb of the loop of Henle, leaving a more concentrated filtrate inside. Salt diffuses out from the lower, thin part of the ascending limb. In the upper, thick part of the ascending limb, salt is then actively transported into the interstitial fluid. The amount of salt in the interstitial fluid, determines how much water moves out of the descending limb i.e the saltier it gets, the more water moves out of the descending limb. This process leaves a concentrated filtrate inside, so more salt passes out. Water from the collecting ducts moves out by osmosis into this hypertonic interstitial fluid and is carried away by capillaries, achieving osmoregulation.
