Gigi was trying to classify an animal as a mammal. What would be the best characteristic of a mammal? A. having lungs to breathe B. giving birth to live young C. giving milk to its young D. having an endoskeleton

Ineed to know why d is the correct answer asap

Fossils can only be formed when? if mud, silt or tar is in the area to preserve the fossil ierosion does not occur and allows the fossil to form oxygen and microorganisms cannot decay the bones the area is dry and does not contain mud or silt

What statements describe a host organism?