How does the structure of cholesterol differ from that of a fat?

Y’all i need answers plss people are saying me and my brother look alike although we’re two different ages. one year apart i’m a girl, btw i’m thinking we could be fraternal twins idk my parents and my friends think we look alike

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Explain why it’s important for scientists to study the sun. list at least two challenges researchers face when examining earth’s nearest star.