Questions

Two series alternate here, with every third number following a different pattern.
In the main series, 4 is added to each number to arrive the next.
In alternate series, 5 is subtracted from each number t arrive the next number.
Here in the main series 
3 + 4 = 7
7 + 4 = 11
11 + 4 = 15
15 + 4 = 19

In alternate series 
24 - 5 = 19
19 - 5 = 14...

Grand Central Terminal also referred to as Grand Central Station or Grand Central is the world’s largest railway station in terms of platforms in New York City with 44 platforms covering 48 acres.

• Cactus spines are also known as modified bud scales, which are also called modified leaves.

• Cactus spines occur in clusters in the axil of leaves.

8-bit processor - 8085/Z80/6800;

16-bit processor - 8086/68000/Z8000;

32-bit processor - 80386/80486