What makes astronomers think there are black holes in space?
1.when galaxies dissapear, they stop emitting infrared radiation, and a hole in space is formed
2.there are areas of space from which no electromagnetic energy of any kind has been deleted
3.at the end of a star's life cycle, it runs out of hydrogen and stops emitting visible light
4.bursts of light that release large amounts of radio waves precede the formation of a black hole

According to this food web which of the following would be considered primary consumers

At which point is crust neither created nor destroyed? island chain mid-ocean ridge divergent boundary transform boundary

Abody cell has been growing and at synthesis proteins.in the nucleus of this body cell,dna replication is taking place. and a copy of the cells genetic material is copied.which of the following is the best conclusion you can make about the life cycle of this cell ? a) the cell is ready to undergo mitosis.and a chemical signal will send the cell to prophase b)the cell is undergoing meiosis and will cross over the genetic material next c)the cell is in the s phase of interphase and will move next to the g2 phase d) the cell is in the g2 phase of the interphase and is ready to begin diving