ROMAN NUMERALS
seven symbols · ones, tens, hundreds · years
$1.50
MAMMALS IN TIME
from the first synapsid to us · 320 million years on one axis
Free
VERTEBRATES IN TIME
when each group appeared · five hundred million years on one axis
Free
BASIC PHYSICS FORMULAS
fifteen formulas · every letter explained beneath it
Free
ANIMALS
the main branches — from comb jellies to chordates · who is actually related to whom
Free
THE TREE OF LIFE
who sits inside whom · where animals, fungi and plants actually are
$1.50
VERTEBRATES
from lamprey to bird · and why "fish" and "reptiles" are not groups
Free
THE BASKETBALL
four FIBA sizes with their circumference and mass — and why the rules set a bounce, not a pressure
Free
FOOTBALL: THE BALL
Law 2, three codes of the game, five sizes and three FIFA quality marks — what a ball must survive
$2.50