Hopkins

Tutor Marked Assignment C

Question 1[pic 1]

Question 2

(a) Hopkins used two sets of rats to show that there was a constant result across and to keep it as a control.

(b)  Hopkins used twenty rats instead of two, to maintain consistency across, to make the results more believable and to make sure it wasn’t a rare thing across rats- rather a common on.  Not only that, but with twenty rats it would be the average result rather than different results for just two single rats.  It’d be more like a one rat versus one rat type of test, which would not be fair, and would not produce reasonable results.

(c) Water, vitamins and minerals were missing from the first group.

(d)  It would make much more sense to use younger rats- as the younger rats did not have as much time in their life to get illnesses and injuries as the adult rats. Since he wanted to test effects on growth, it's much more reasonable to use young rats rather than adult ones because growth in adult rats is not very much significant.  Also, adult rats had much more time to grow and become bigger than the younger rats- they would need more food and nutrients to keep them healthy than the younger ones.

 (e) It is very important for the diets to be switched between the two groups after 18 days, just in case perhaps one of them fall ill, or one of them has a rare type of illness or disease, or some of them are strangely odd rats- switching the diets between the groups would balance the results.

(f) Some important control variables to bear in mind in this experiment, would be the amount of time the rats sleep, the amount of exercise they do, and the types of rats being used.

Question 3

(a) B

(b) B

(c) C

(d) G

(e) A

(f) D

Question 4

(a)   i. Salivary glands  ii. Small intestine- as absorbed in the villi

(b) Salivary glands and pancreas

(c) Small intestine

(d) It joins up to form a large blood vessel, via the hepatic portal vein, to the liver.

Question 5

(a) The stomach not the organ that "digests" the food rather it is the enzymes and acid that the stomach wall secretes- that does so. The muscles of the stomach simply contract to aid the digestion It’s muscles  also contract periodically, churning food to enhance digestion. Most of the digestion occurs later in the small intestine.  I would say “The function of the stomach is to secrete gastric juice that breaks down and churns the food substances; enhancing the digestion process”