From doppler shifts of the spectral lines in the light coming from the east and west edges of the sun, astronomers find that the radial velocities of the two edges differ by about 4 km/s, meaning that the sun’s rotation rate is 2 km/s. find the approximate period of rotation of the sun in days. the circumference of a sphere is given by 2πr, where r is the radius of the sphere.

dopamine..

"it was found that some people who were taking the drug l-dopa to raise their levels of dopamine were developing schizophrenic-like symptoms supporting research a strength of the dopamine hypothesis is that there are many studies which have shown support for the neurochemical explanation."

i think they are all correct

explanation:

they seem good

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg