A student noticed that when a dog is cut, the dog periodically licks its wounds. Usually after a few days..?

Question

A student noticed that when a dog is cut, the dog periodically licks its wounds. Usually after a few days, the wound begins to heal without ever showing signs of infection. The following steps outline the student's line of reasoning:

A. I wonder why the dog's wound doesn't become infected.

B. The dog's saliva must prevent the growth of infection-causing bacteria.

C. I'll obtain a bacterial culture and grow the same kind of bacteria in two identical culture dishes. Once the bacteria start growing, I'll add dog saliva to only one of the dishes and leave the other alone. I'll cover both dishes. Then I'll observe what happens each day for a week.

D. Even after adding the dog saliva to one of the dishes, the bacteria continued to grow in both dishes over the course of the week. However, the bacteria in the treated dish grew more slowly than the bacteria in the untreated dish.

E. I think I'll try something else. I'll start with two identical culture dishes, as before, and use the same kind of bacteria in each dish, but this time I'll treat one dish with dog saliva before I add the bacteria. I'll observe what happens each day for a week.

14. Why might the experimental design in step E be a better test of the student's hypothesis than the design used in step C?

(5 points)

Answer 1

Wow, just shows that students have far too much time on their hands to be playing about with dog dribble!

I'd say E is a better design because in C, the bacteria is already growing, but a dog only licks the wound as soon as it happens, not after there is bacteria.  So it is testing to see whether the l**k is protecting against infection.

Answer 2

LMAO....do your own homework.

Answer 3

B

Answer 4

I dont know..  maybe because the dog would l**k itself before the bacteria has a chance to set in and grow?

As a 3rd test, the student should try adding the saliva several times a day to see what happens..  consider the fact that a dog would l**k itself more than once!

Also howabout a dish that has nothing but the dog saliva to see if there are bacteria in the saliva that may be killing the infection-causeing bacteria.

Answer 5

I have a solution to your problem:

GET OFF OF THE COMPUTER AND DO YOUR OWN HOMEWORK!

Hope this helps!

Answer 6

umm is this ur hw?

Answer 7

haha, you typed ALL that, but know one can help you!!

Answer 8

HAHAHA. Nice, use the Internet to answer your homework. =]

Well, the answer...

The experimental design in step E might be a better test of the student's hypothesis than the design used in step C because the dog's saliva prevents bacteria from starting to grow. In step C the saliva was added after the bacteria started to grow. In step E, the bacteria will not have a chance to grow because the dog's saliva is already on the food. Step E might be a better test because if the bacteria does not grow, that would mean the saliva does not stop bacteria, it prevents it.

BTW, your level one. You cannot give me five points...

"BEST" my answer and I'll be happy thou. :)

Sincerely,

Just another average girl.