Answer:
Blastula
Explanation:
This mass of cell – called blastomere- surrounds a fluid-filled cavity-blastocoele- formed in the very early stages of development of an embryo in animals, after fertilization and the formation of a zygote. Blastomere cells have high potency and can differentiate into any type of cell.
The smallest unit of classification is species.
Animal Types and Characteristics
Mammals:body covered by hair or furwarm-bloodedhave a backboneproduce milk
Reptiles:body covered by scalescold-bloodedhave a backbonemost lay hard shelled eggs on land
Birds:body covered by featherswarm-bloodedhave a backbonelay eggs
Insects:most are small air-breathing animals6 legs2 antennae3 body sections (head, thorax, abdomen)Spiders:also termed arachnids8 legs8 eyesthey spin webs
Aquatic Animals:most have gillsfound in lakes, rivers, and oceans
Dendrochronology, or tree-ring dating, provides absolute dates in two different ways: directly, and by calibrating radiocarbon results. Cross-dating determines the age of undated wood by directly matching ring patterns with trees of known age.
Hope this helps ^^
