These closed tubes can circulate water and nutrients, and carry off wastes. Kingdom Animalia Kingdom Animalia includes 35 phyla and over 1 million species. Animals are diploid, eukaryotic and multicellular. All animals are heterotrophic. And all animals respond to external stimuli.
All animals are motile, moving about at some point in their life cycle.
Only animals can fly. J.B.S. Haldane once called animals wanderers in search of spare parts. All animals reproduce sexually by forming haploid gametes of unequal size, the egg and the sperm. The gametes fuse into a zygote , which develops into a hollow ball of cells called a blastula . In most animals, this hollow ball folds inward to form a gastrula , a hollow sac with an opening at one end, the blastopore , and an interior space or blastocoel .