"I think its when the ovum is fertilized and starts to divide?" said Rhys, "It starts as two, then four, then eight, then sixteen. From the moment its sixteen cells, its got everything in it to make a new person."

"DNA," I said, "It's all written in the DNA. That's where life begins!"

"I don't understand that," said Rhys, "Old Mac tried to explain it to us last week. It was too difficult for me."

"I think I got the general drift," I said, "There's strings inside every cell, with codes, written in chemicals, which have all the details about us on them. When a cell divides, it makes a copy of itself."

"You mean if you took a cell from my arm, or head or anywhere, you'd be able to find a coded copy of me in it?" said Rhys.

"That's right," I said, "Its all coded information. Really small! Amazing isn't it."

"That's what they said in the movie Jurassic Park," said Rhys, They got some blood from an insect which sucked it from a dinosaur. The insect died and got itself covered in amber, then years and years later some scientists got the blood and used it to make new dinosaurs."

"The only problem is," I said, "There isn't much DNA in blood cells, so it wouldn't have worked very well. Blood cells don't have DNA."

"Well that's a but stupid!" said Rhys, "The only bit of science to base the whole movie on was a shonky mess!"

"That's what science is like," I said, "You can't always trust it. Sometimes they just make it up, or they fiddle the numbers! They make guesses all the time. I read about the first trains once. Did you know there were scientists around who said if a train went too fast all the air would be sucked out of the carriages?"

"Well they sure were wrong!" said Rhys laughing, "Trains go like bullets these days!"

"And there were scientists who said that light always travels in a straight line, but now we know it curves everywhere."

"Does that mean the universe might be round like a ball?" said Rhys, "That would be weird wouldn't it. You could start off on one side of planet earth and fly straight away from it, but in the end you'd come back on