JN.

Well, I think the logic is "if your body expelled it, then it's not useful". However, urine has also water so, in an emergency, I think we can drink urine without fearing for our health, although the probability of being drinking some pathogenic bacteria. Moreover, I think that an healthy adult can metabolize again the wastes of its urine, so it will not be prejudicial. But you're not asking if drinking urine is dangerous, but precisely the opposite. Well, I think it's not. And since we cannot find any scientific evidence to support this, I guess that we can assume that drinking urine isn't healthy.

I think that one of the best examples of that are related with carnivorous plants. They produce nectar which attracts small insects, but then the insects get caught by the plant and are digested by them.

Life can exist in extreme conditions, and the extremophiles are an excellent example of that. But extremophiles are mainly bacteria, and bacteria are not animals. And sigle-celled organisms are not animals, too. One common characteristic to all animals is that they are multicellular.

Well, I admire a lot of scientists, but I think one of the most inspiring examples comes from Marie Curie. I think that she's an example as a scientist and as a person. And with her I learned a thing that I realized how important it is only a few time ago: ideas are far more important than biographies, and it does not matter if a very famous scientist says something, because we are all able to judge its ideas and to verify the truth of its words. I don't know the worst example.. Maybe Georges Cuvier. He was dependent of the public opinion and he did not try to find hypothesis that could match the evidences; he just try to adapt the evidences to the conclusions he was expecting.

Some fungi organisms are also single-celled, such as yeasts. We do think, at least today, that the first ogranisms to appear were unicellular and simple ones, called procaryota. For example, bateria are procaryota, and they can be distinguished for they have not organels inside separated membranes. Then the eucaryotic cells appear. The eucaryotic cells are bigger thant the procaryotic cells, and have different organels inside them, such as mitochondria. Our cells are eucaryotic, for example. We do think that some organels, such as mitochondria and chloroplasts (and many other plasmids) were first independent procaryotic organisms, which suffered phagocytosis of a bigger procaryote organism. They were not digested, which means they stood inside the biggest cell, and they were kept there, because they could help the bigger organism getting some nutrients or converting them to energy. For the small organisms, being inside a bigger one was advantageous, because they were protected from other predators. That's how we think now that eucaryotic cells evolved. By the way, we think that first appeared mitochondria, and only then chloroplasts, because although all eucaryotic organisms possess mitochondria, only plants have chloroplasts. Then eucaryote cells gathered in colonies, and some cells became specialized in some functions, such as reproduction or locomotion. Although they were living in colonies, they could leave it, as they were independent organisms. However, they evolved to multicellular organisms. In multicellular organisms, the cells that compose them are not individual organisms, because they are all dependent of the other cells. That's how I think evolution to multicellular life occured, and I think it is the most accepted theory. And, of course, single celled organisms persisted because they were also well adapted and evolution did not kill them. Not always multicellularity and a big size are a symbol of success.

I already understand how to balance a redox reaction, considering the environment in which they occur. However, I do not understand why do we need to consider that. I mean, why do OH- and H20 and H+ interfere with the reactions?

Hi! Today I was taking care of my plants, and accidentaly my hoe beated in a stone and I saw a spark. Does anybody know what happens with the atoms? The first thing I thought was the work done by the shock energizes the atoms, and when the atoms get de-energized, resulting in the spark. However I thing that this is not a good interpretation of that.

I think this problem seems to be about maths, but if we look closer, we'll see that this is just to make people laugh. I think that the most important here is that grass grows continuously, so it's impossible for the animals to eat them all. I think that's how it should be interpreted but, of course, I may be wrong.

1.1) Well, I have not the right to judge the people tied to the track, so I can't say it would be better to kill one and save five. As I'm not responsible for mad philosopher's acts and I can't save everyone, I wouldn't switch the train. 1.2) No. The fat man is an innocent person here. He has nothing to do with the mad philosopher's actions and he should not be seen as a sacrificial animal. As I think one's life has an infinite value, the value of the fat man is equal to the value of the five people tied to the track. So, I wouldn't kill an innocent without knowing is will to save anybody. 1.3) I woud throw him. I would be defending five innocent people without harming innocent people. We must be responsible for our actions, and if I threw the philosopher I would be making him pay for its actions - an eye for an eye. 1.4) If I knew previously the man who were sleeping would be killed, my answer would be the same as I gave in 1.2. 1.5) First and foremost I must say I would prefer saving people I know than people I don't know, because they're, obviously, more important to me. In addition, I think we should not expect everyone to sacrifice its life to save somebody, so I would not call the person tied in the left track as being imoral, since it is not responsible for the people who are in danger. 1.6) The health of the people tied don't change my answer, although it would make it easier to turn my back. 1.7) No, it's not the young's fault if the life of the other 5 people is at risk. Why should he be sacrificed?

I support the women's right to abort. I think that when we're speaking about abortion most part of people only thinks about the foetus, and forget the woman's right over her own body. The same way I should have the right to make a tatoo, I should have the right to remove a kidney if I wish so or, in the case of a pregnant woman, to remove her baby. However, if the foetus can survive outside its mother womb, he should not be killed, for it is an independent life. Now speaking about the hypothetical situation on the first topic: in my opinion, no one have rights over other people, except governments if the person in question is a criminal. In consequence, the French King is commiting an imoral act, because is forcing another man to save his son. It doesn't matter if other human life is being saved, because the important here is the individual, and not the fact of belonging to the Human race. After all, we're all different and we're expected to respect others individuality (and to see our own respected). However, if the Spanion wants to help the prince, I think it's fair, even if the spanion man dies during the process. And I also think the spanion have the right to demand money for that.

Why do you say your friend was taught to be gay? Although gay pride do exist, families do not encourage their children to be gay. In fact, families are always reproving all sexual orientations, except heterosexuality, of course. This should result in children "choosing" heterosexuality. However, there are gay children. Maybe this should be a fact against the nurture explanatory theory on homosexuality. Why are you trying to "cure him"? Does he appears to be suffering? In affirmative case, maybe you should ask him what's making him suffering. Why will homosexuality be a problem in the future? Do you think the number of gay people will overcome the number of straight people? I don't know what you think about this, but I think it's quite improbable.

I think it would be easier if you took the interphase. The interphase has three characteristic steps: G1, S and G3. The G1 concerns the cellular growth, and happens right after the cellular division and the formation of the cell. S stands for the replication of the DNA molecule. This molecule should be correctly copied, to avoid mutations. G2 is related with the duplication of other organelles. This duplication will prepare the cell to divide itself. So as you can see, either DNA molecule and organelles are divided; however, although the DNA molecule is correctly (under ideal conditions, of course) duplicated, the other organelles are not. This means that during cytokinesis it's not important to made an equal division of the organelles, because the two resultant cells are able to create those new organelles, because of the information of the DNA strand they receive.

We must, after saying homosexuality is or is not a mental illness, say what a illness is. In my opinion, a disease is a condition of our body or mind that make us suffer or that can destroy us (and with "destroy" I mean kill us or making us incapable of living a life with quality). Thinking about this definition, I think that homosexuality should not be considered to be a mental illness. Homosexuals do not have any physical problem, neither a psychological one, because homosexuality is not directly related with some cases of depression or suicide. Some people say homosexuals have a mental illness because we can see that the most part of teenagers who commit suicide are gay; however, their depression is derived from the social pressure, and not from their sexual orientation. To prove that this is a fact and not a theory developed to protect gay rights, we can - and we should - analyse how homosexuality is seen in other cultures. For example, we can pick the Etoro tribe; homosexual behaviour (yeah, I know it's different from homosexuality...) is encouraged by the tribe, so the most probable to be seen is that gay teens and straight teens have not different suicide rates. It's pure speculation, because I don't know any data on this, but it would be an interesting thing to study. And I know there are more tribes who encourage homosexuality and where heterosexuality is not the the rule. This should also prove that homosexuality is not dangerous to any society, because if it was, it would be avoid by all societies. *I don't know if I wrote the whole message without mistakes but, if I didn't, I would like to know! *

It was because of the impossibility of proving something only with verification that Popper developed his theories of falsiability. In fact, proving that all crows are black empirically is also impossible, because we can't prove there are no more crows in other part of our world. That's the old story: we cannot prove the non-existence of something.

I think that parents of adopted children should tell their children they're adopted as soon as possible. At the age of 18 is, in my opinion, too late. I think that if a child is told it is adopted, the acceptance will be better.

And we can assume that alkali metals have always 1+ and alkali earth elements have 2+. Oxygen can vary from 1- to 2-, although it's more common to be 2-.

Since there are not consensus about considering viruses as being live organisms or not, I think we cannot speak about our proximity to viruses. That's just my opinion, however.

Fertile eggs would be chosen by Natural Selection, but hens have been chosen by artificial selection. The characteristics "chosen" by natural selection are those who allow animals to breed more than their partners in a wild state; when we're speaking about artificial selection, the characteristics that matter are those more favorable to the selector. The evolution of dogs or cattle are also similar: their characteristics would not allow them to survive in a wild state, but are favorable to men.

Hello everybody! I'm new here, and I just want to introduce myself. I'm from Portugal and I want to study Biochemistry at the University. I hope here I'll find good information about this subject and learn something with the experience of other users.