The cells that develop to form the outer lining of an animal's body make up the _[blank]_. blastula endoderm ectoderm mesoderm

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

Hurry which of these is true about index fossils? a) are very scarcely found b) used as guides in relative dating c) found in the youngest layer of the rock d) used as reference points in absolute dating

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?