I need help QUICK!! 20 points Which of the following is/are formed as gravity pulls increasing amounts of dust and debris in a nebula together?

a. the solar wind

b. meteors

c. planetesimals

d. meteorites

Abeam of electrons with of wavelength of 7.5 x 10-6 m is incident on a pair of narrow rectangular slits separated by 0.75 mm. the resulting interference pattern is projected onto a screen 10.0 m from the slits. what is the separation of the interference maxima in the resulting interference pattern?

How do we measure or think of speed in the united states?

Which statement is the best definition of an atom? a) anything that has mass and occupies space. b) the smallest particle that has the properties of an element. c) a substance that cannot be broken down chemically into simpler substances. eliminate d) the smallest unit of a substance that exhibits all of the properties characteristic of that substance.