Which is a compound? A. Orange and black shirts in a drawer
B. An alloy of copper and iron
C. Silicon and carbon in a molecule
D. A copper statue
please help, on a pex ! brainliest and an extra 50 points if right

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?

Which of these statements best explains why space exploration should be encouraged? it prepares humans to live without oxygen. it dispel myths about objects in space. it prevents comets and asteroids from striking earth. it creates technology to absorb harmful radiations in space.