Most Popular
1500 questions
24
votes
5 answers
Why does the cold make us sick?
From the moment we learn to communicate, we always get told, whether by our parents, or our teachers, or by anyone else, to avoid the cold, or to put a jacket on to avoid catching a cold, to dry our hair before we go outside, because we'll get sick…
JohnPhteven
- 614
- 2
- 6
- 17
24
votes
2 answers
How does the microbial environment in your gut initiate?
Clearly, a zygote does not harbor any microbes. As it develops, and the alimentary canal tissue is differentiated, I logically assume that there is still no microbial activity in the fetus's gut. I'm thus also assuming that the commencement of…
LanceLafontaine
- 6,705
- 8
- 36
- 78
24
votes
2 answers
Why is it advised that infants are fed mother's milk?
I have heard that mother's milk is preferred over other baby foods, because it contains immunoglobulins (secretory IgA), and other essential nutrients.
But why is mother's milk so special? Any mammalian milk, such as the widely available cow's…
Mehul Sharma
- 351
- 2
- 5
24
votes
3 answers
Why don't rats have a gallbladder, unlike other rodents?
It has long been known that rats do not have a gallbladder, though other species including humans, monkeys, cows, reptiles, dogs and mice, all have a gallbladder.
In this paper from almost 100 years ago, scientists were studying what differences the…
Vance L Albaugh
- 2,378
- 4
- 23
- 44
24
votes
2 answers
How do burrowing animals get enough oxygen?
Tree borers make a small hole in a tree. At the end of it, they chew on wood to elongate the tunnel. They digest food and grow. All this takes oxygen.
The entrance to the tunnel is generally small. Some borers plug the entrance. Even without that,…
mmesser314
- 376
- 1
- 9
24
votes
3 answers
Why do we laugh?
Why is it that the reaction we get from absurdity is laughter? Everyone does it, even babies. Is there a reason why it is our instinct to laugh when we see or hear something absurd/humorous
Small Legend
- 343
- 1
- 6
24
votes
2 answers
What magnification do I need to see blood cells?
If I want to buy a microscope for my kids to be able to view single celled creatures and blood cells, about what magnification is required? A Celestron Pentaview digital scope claims up to 600×. Is that going to be sufficient? I somehow get the…
Octopus
- 540
- 1
- 3
- 14
24
votes
2 answers
How many human cells are there in our body, on average?
How many human cells are there in our body, on average?
Wikipedia says 1013:
Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in the body (approximately 1014 versus 1013).
The…
Sklivvz
- 351
- 1
- 3
- 10
24
votes
6 answers
What determines the spiral direction of plants?
Some plants and vines spiral clockwise as they go along (right direction) and some spiral anticlockwise (left direction). What determines which direction they spiral along? At first, I believed it to be determined by which hemisphere you are in…
QCD_IS_GOOD
- 383
- 3
- 11
24
votes
1 answer
Why do adults lose hearing at high frequencies?
Children and teens can hear high pitched sounds that adults can't hear anymore. Why do adults lose high-frequency hearing?
ZZZ
- 816
- 3
- 12
- 18
24
votes
1 answer
What's the smallest size a human eye can see?
During a biology experiment at school, where we would look at waterweeds under a microscope, my teacher said something about that it's impossible for the human eye to see the cells without a magnifying glass of some sort. So, I saw that as a…
Joeytje50
- 343
- 1
- 2
- 7
24
votes
3 answers
Hot water and bacteria
I know that it is common to say, "use hot water when washing your hands" or when you've got a cut, "wash your hands with warm water," etc. I was wondering, why is this the case? Since bacteria grow in warm environments, you would think that it might…
TanMath
- 3,079
- 3
- 29
- 41
24
votes
1 answer
Why do we have five fingers?
Humans (and other humanoid mammals) have five fingers in each hand.
Curious to know, why five? Wouldn't more fingers be more useful?
Is there any evidence that it used to be different and natural selection caused those with five fingers to survive?
Shadow Wizard Love Zelda
- 651
- 1
- 5
- 17
24
votes
2 answers
How fast does the rotor in ATP synthase spin?
I'm sure the exact frequency varies, but does anyone know roughly how many revolutions per minute / second the rotating center part makes?
Shep
- 2,505
- 2
- 21
- 29
24
votes
1 answer
Phagemid display
If I'm using a bacteriophage for phage display and I'm trying to avoid avidity effects by using a helper phage what would be the best way to maintain a large library size while keeping everything monomeric? I'm asking in terms of maintaining an…
bobthejoe
- 7,867
- 7
- 43
- 73