Questions

Let the required number be 'X'

Condition 1 :  

$$\begin{gathered} XX = 2X \\ => 2X2 = X \\ => X = 12 \end{gathered}$$

Condition 2 :

$$\begin{gathered} X × X = X2 \\ => X = 12 \end{gathered}$$

Therefore, 12 is the number which becomes double when it is divided by itself and becomes half when it is multiplied by itself.

All the above listed are the System calls for process management

Isthmus of panama and Isthmus of Suez are well known examples

A Sandal.

It has sticking strips to make them fit for our feet. If you bind them only you can start walking or other wise it comes out.

In a first, China is planning to send mini-ecosystems — containing potato seeds and silkworm eggs — to the Moon next year, in an attempt to study how the organisms develop on the lunar surface. The 3-kilogramme mini-ecosystem, developed by research teams led by Chongqing University in China, will be sent to the Moon by the Chang’e 4 scheduled to be launched in 2018, authorities announced at the Global Space Exploration Conference. An 18-centimetre-tall cylinder will carry potato seeds and silkworm eggs to be incubated.