1.which of the following describe the study of planes in their orbits ? a. physics b. chemistry c. astronomy 2. how are physics , astronomy and chemistry connected ? a. each discipline uses principles from each other b. they are not connected they are separate felid of study c. chemistry and physics are connected while astronomy relies on completely separate principles

1 - C

Through the process of elimination, you can find this answer. Physics is motion and gravity while Chemistry is chemicals reacting and etc. 

2 - A | Each discipline uses principles from each other.

Astronomy relates to gravity and the pull of things which relates to Physics. Astronomy also has millions on chemical compounds towards the periodic table which relates to Chemistry. Chemistry and Physics work hand in hand; how reactions for certain chemicals work and how it affects movement and how things function.

Although A isn't entirely the correct answer, it is more than likely what your teacher wants. Astronomy and Chemistry are subsets of Physics so...

Hope this helps!

Can you add a picture of the question?