What is meant by density material?

Plzz worth 10 ! which statement about energy transformations is not true? a all forms of energy can be transformed into thermal b energy is never destroyed or created during transformations c potential chemical energy always transforms into kinetic d some thermal energy is always released during a transformation

Astronomers discover an exoplanet (a planet of a star other than the sun) that has an orbital period of 3.87 earth years in its circular orbit around its sun, which is a star with a measured mass of 3.59 x 1030 kg. find the radius of the exoplanet's orbit.

Zeros that follow non-zeros numbers and are also to the right of a decimal point are significant