Insulin released to prevent the surge of sugar in bloodstream when glucose increases.
Answer:
Dune vegetation would miss a significant source of nutrients if sea turtles go extinct and would not be as stable and not large enough to support the dunes, resulting in increased erosion.
Explanation:
While their range is wide, due to extensive egg collecting and bycatch fisheries, the numbers of leatherback turtles have decreased dramatically over the past century.
Marie and Pierre Curie successfully isolate radioactive radium salts from the mineral pitchblende in their laboratory
Answer:
d. Fluoride becomes incorporated into the crystalline structure of teeth, making them less susceptible to decay
Explanation:
Dental caries results when cariogenic (caries-causing) bacteria metabolize carbohydrates or sugars present in the mouth for their energy needs, producing organic acids as byproducts, thus lowering the pH of the plaque biofilm.
The hydroxyapatite of tooth enamel is composed mainly of phosphate ions (PO₄³⁻) and calcium ions (Ca⁺). Under normal conditions, there is a stable equilibrium between the calcium and phosphate ions in saliva and the crystalline hydroxyapatite. At low pH (acidic conditions), there is a shift in equilibrium resulting in the dissolution of hydroxyapatite from tooth enamel, a process known as demineralization. A reverse process called remineralization (the process of incorporation of minerals in tooth enamel) occurs when the saliva, acting as a buffer elevates pH. When equilibrium is shifted to favor continued demineralization, dental caries results.
However, when fluoride is present in saliva, fluorapatite, rather than hydroxyapatite, forms during the remineralization process as fluoride ions replace hydroxyl groups in the formation of the apatite crystal lattice.
Fluorapatite is less soluble than hydroxyapatite making it more resistant to demineralization, even under conditions of low pH. Thus, fluoride acts as an effective anticaries agent.
Does not absorb moistures: Man-made fibres do not absorb sweat, trapping heat in our body. Rough feel: Man-made fibres may give the rough feel, making it unsuitable for pyjamas, underwear, etc. Some individuals are often prone to skin allergy, because of the dermatological action of Man-made fibres.
