Is everything scientists say true?
No not always! Scientists make mistakes just like regular people. So don't belive everything they say because everything they say isn't true! If scientists said if you touch a person with your eyes closed and they turn purple right away would you believe it? No of course not. Scientists don't know everything only God does.
When scientists are skeptical, the are more likely to find new thing. When scientists are not skeptical, they are less open to opportunities. For example, if scientists were not skeptical of the idea the Earth was flat, then they would have continued many many more years without knowing the true shape of the world. Also, without scientists skepticism, they would not have found out that the planets rotated around the sun, not that everything rotates…
They do not have evidence. In fact most pf things are not even true. The only thing they say they did was put a stick on the ground and with a shockwave they knew what was inside the earth. My opinion is that the core is not what scientists say it is. Due to the fact that we know more about the moon than our own planet.