When people or cockroaches undertake a difficult task, the presence of others performance; whereas when they undertake a simple task, the presence of others performance.

impair;enhance.

Explanation:

the blank will be filled with impair;enhance.

When undertaking difficult task the presence of others degrade or weakens  the performance of the people.

And when undertaking the simple task the presence of other enhance the  performance of the group.

This is because difficult work require more concentration and presence of other person affect the efficiency of the person.

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.

because this was the year that the state of israel was formed