Most organic acids are weak. Hydrogen fluoride (dissolving in water to produce hydrofluoric acid) is a weak inorganic acid that you may come across elsewhere.
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acid Ka (mol dm-3)
hydrofluoric acid 5.6 x 10-4
methanoic acid 1.6 x 10-4
ethanoic acid 1.7 x 10-5
hydrogen sulphide 8.9 x 10-8
Answer:
Attract the female attention
Explanation:
Male sage grouse have feathers to the toes, pointed tail and legs, two inflated air sacs on the neck, brown throat and black belly. In the mating season, many male sage grouse gathers in an open area do courtship display to attract the females.
In their courtship display, they erect their feathers like a peacock do and make blooming sound by inflating their air sac. Females choose that male sage grouse which seems to be more attractive to them and mate with that male sage grouse. Therefore the function of this dance is to attract female attention.
Answer:
Glucose entering the intestines from the villus.This is by active transport.The latter is defined as the movement of molecules and solutes from the region of lower concentration to the region of higher concentration against the concentration gradient.
Explanation:
All the above options depends on the diffusion gradients from one higher region to another.e.g oxygen passing from high concentration from outside to lower concentration in blood stream,like wise Co2 from higher concentration from inside to outside,with passive diffusion lipids and water enter the small intestine(note amino acid and glucose,and fructose are different).
Active transport( through sodium dependent transporter) transports glucose to the intestine from the villus.This is movements against concentration gradient because,glucose molecule are concentrated in intestine,and needed by the cells, in the body.Therefore they must be transported as a fast rate inn the blood .
However the absorption by the villi is very slow,therefore active transport is needed to move these against the concentration gradient into the intestine.And finally the blood.
If this were to be moved by passive diffusion,the high concentration in the intestine will force this back into the villi
Therefore extra energy is needed by active transport for the glucose molecules to enter the intestine from the villus.
