Ithink i know the answer but i am not sure

which shows how many centimeters are in 3.14203 × 10-4 to three significant figures?

a.
3.14 × 10-1 mm

b.
3.14203 × 10-1 mm

c.
3.10 × 10-1 mm

d.
3.142 × 10-1 mm

The act of moving from one place to another. a. locomotor b. aerobic c. stationary d. static

Can anybody me with this? ? (picture included.)

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?