The answer to your question is -2
Answer:
Early experiments on children don't fit today's standards of ethical treatment.
Explanation:
Today, because of advances in ethical considerations scientists would not conduct this experiment never the less get approved to do it because an infant would not be able to speak up and make decisions.
Gravitropism
Phototropism
Thigmotropism
It turns out that many materials can be solid at a higher temperature if the pressure is also higher. so even though it is hotter in the inner core the pressure in the core is also higher and you can have a solid iron nickel instead of liquid
I think it might be C I am not 100% sure though
