Scientists found cities of brittle stars living on the ocean floor. study the picture of the star below. what is the order of rotational symmetry for the star?

a.0
b. 5
c. 1
d.4

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope