Does the number of particles change as a substance changes in state?

Which of the following statements is true? 1. the mantle of the earth is made of solid nickel and iron. 2. the crust of the earth is made of solid nickel and iron. 3. the inner core is made of solid nickel and iron.

Choose the correct words to complete the sentences related to genetic screening. is a procedure that is used during pregnancy to detect genetic defects. is extracted from the uterus and used to identify genetic disorders?

Witch theory suggests all living things are made up of cell or cells