Questions

The nearest stars to Earth are in the Alpha Centauri triple-star system, about 4.37 light-years away. One of these stars, Proxima Centauri, is slightly closer, at 4.26 light-years.

Of all the stars closer than 15 light-years, only two are spectral type G, similar to our sun: Alpha Centauri A and Tau Ceti. The majority are M-type red dwarf stars.

Only nine of the stars in this area is bright enough to be seen by the naked human eye from Earth. These brightest stars include Alpha Centauri A and B, Sirius A, Epsilon Eridani, Procyon, 61 Cygni A and B, Epsilon Indi A and Tau Ceti.

Concatenation of text means adding a word with other word. It can be done using Ampersand (&).

For example :

'Amper' & 'sand' = Ampersand 

DNA is the genetic material in the cell. 

Hence, option B) DNA is located in the nucleus best matches the description with the genetic material.

STARTLING is a required 9 letter English word is still a word each time you remove a letter from the word. And how it is shown below: 

1. Remove the L, and the word becomes: STARTING

2. Remove one T, and the word becomes: STARING

3. Remove the A, and the word becomes: STRING

4. Remove the R, and the word becomes: STING

5. Remove the other T, and the word becomes: SING

6. Remove the G, and the word becomes: SIN

7. Remove the S, and the word becomes: IN

8. Remove the N, and the word becomes: I