Have* this is because has* is past tense and have is more appropriate since there are multiple things you are referring too (Mercury, Venus, Earth and Mars). To be honest, these planets have a molten core.
Heavenly, delectable, tasty. Connotation is like how strong the meaning of the word is and I'm pretty sure heavenly would go before delectable.
Answer:
Ist
Explanation:
Scientist, Phycologist etc