The Body Cavity that protects the brain is enclosed in bone. Why do you think the abdominal Cavity is not enclosed in bone?

The earth formed roughly 4.5 billion years ago, yet evidence of life dates back to about 3.5 billion years ago. which one is not a possible hypothesis of how life on earth arose?

Ineed a little . why do you think there is a basic difference between the kinds of fertilization most common in aquatic and terrestrial animals?

Analyze how the four requirements for life were identified by scientists