Yes, they can see people.
People like guppies because they are small and cute
Guppies are livebearers. So they don't lay eggs. Male guppies WILL eat their own baby guppies. They will eat any baby guppy they see. It doesn't matter if it's their own or some other guppies'. Male and female guppies eat baby guppies.
Guppies are fish. They do not have personalities like people do. They have evolved instincts and behaviour patterns.
Bubble guppies
You can not see through Guppies. You may well be able to see into some of them and see some of their internal organs. The reason for this is the lack of reflective material in some of their scales which allows some light to penetrate thus allowing some vision.
See related links below
I'm not sure but some people say you should or the baby guppies will breed.
Yes. Freeze dried worms are safe for guppies but lots of people have had problem with baby guppies because they are too small to eat the freeze dried bloodworms.
The answer depends on the number of guppies. A few guppies can live in a 2.5 gallon tank or larger, temperature between 72 and 80 degrees Fahrenheit. Many people raise fancy guppies in 5.5 and 10 gallon tanks.
Fries (the term for baby guppies), are eaten by older guppies, but guppies are eaten by fish like tuna.
Only guppies breed with guppies naturally.
What are guppies