Very good question Mirabella,
Well it actually happens in many species, not just us humans. Lots of birds have different male and female appearances.
Its called “sexual dimorphism”. We are different so that we can recognise a person of the other gender, when it comes time to having children, because you can only have children with someone from the opposite gender to you.
Well mirrors work basically by reflecting, or bouncing back light which hits a smooth, shiny surface. When a photon of light hits a mirror, it makes the electrons in the atom vibrate and bounce off an identical photon of light – this is reflection.
Now question 2, thats a little more difficult – gender is a complex question – originally rooted in biology, its now got an important role in society and personal development. Biological gender is what makes males and females different – whilst we still have the same basic design, we have different hormones, different brain connections and different physical traits.
The idea of 2 genders is connected to what Shane has already said – by having 2 genders for reproduction, you are ensuring that the result of this mate will be genetically similar, yet different to the parents -encouraging diversity in the population!
Two in one! thats my favourite kind of question 🙂 And you guys did a great job at answering these questions! I ll only add a little to these answers. Ok, so how do mirrors work? When a photon of light hits a mirror it causes the electrons in that atom to vibrate and give off and identical photon of light. Metals work better as mirrors because they have many electrons shared by all the metal atoms. Mirrors need to be smooth for the light to be reflected and go straight back to where it came from (you), instead of being scattered in a different directions (you wouldn’t be able to see yourself in the mirror if it did this). Most mirrors in our everyday life have three layers. The bottom layer is a dark, protective layer. The middle layer, the most important part, is made of a metal, usually aluminum, and the top layer is made of glass, because its clear and it protects the smooth aluminum layer. Great question Mirabella! Hope that helped answer your question 🙂