A control group in a scientific experiment is a group separated from the rest of the experiment, where the independent variable being tested cannot influence the results. This isolates the independent variable's effects on the experiment and can help rule out alternative explanations of the experimental results.
A wind instrument is a musical instrument that contains some type of resonator (usually a tube), in which a column of air is set into vibration by the player blowing into (or over) a mouthpiece set at or near the end of the resonator. The pitch of the vibration is determined by the length of the tube and by manual modifications of the effective length of the vibrating column of air. In the case of some wind instruments, sound is produced by blowing through a reed; others require buzzing into a metal mouthpiece.
<span>the Fair Debt </span>Collection Practices Act, also know as the <span>FDCPA
(i know this is probably a little late) sorry :( </span>
<u>Answer</u>:
The mass of a star can be determined by studying binary star systems.
<u>Explanation</u>:
In this system it consists of two stars, revolving round the same bary-centre. The systems having two or may say more than two are called as the multiple star system. This zone is also a habitable zone, here the water exists in the liquid form. We could have sometime seen the two stars together. They are also very capable of strengthening the terrestrial planets inside the stable orbital ranges. They have generally two orbits like P-type as well as circumbinary.