Our immune system is armed with an array of defenses designed to detect and eliminate harmful threats. One of its most powerful defense mechanisms is the complement system—a group of proteins that ...

This internal left-right asymmetry is believed to begin at the very early stage of development -- when a tiny embryo is divided into two parts during a process called gastrulation. This process ...

Dinosaurs had sex. Fossil nests and eggs, as well as the ways today’s birds and crocodiles reproduce, leave no doubt on that ...