What is the major cause of earths magnetic field

What happened to rosalind franklin in 1956?

Flock x flock y flock z total pieces of food eaten (from previous page) 147 93 60 food percentage* % % % simulated number of birds in flock for 3rd generation** * divide each flock's total pieces of food by 300, the total number of pieces of food eaten. ** multiply the food percentage for each flock by the total number of birds (30).

What was the land like over 500 million years ago? what was under the sea?