QUES: These quarks and leptons interact through four fundamental forces: gravity, electromagnetism, weak interactions, and strong interactions. The Standard Model of particle physics is currently the best explanation for all of physics, but despite decades of efforts, gravity cannot yet be accounted for at the quantum level; it is only described by classical physics (see quantum gravity and graviton). Interactions between quarks and leptons are the result of an exchange of force-carrying particles (such as photons) between quarks and leptons. The force-carrying particles are not themselves building blocks. As one consequence, mass and energy (which cannot be created or destroyed) cannot always be related to matter (which can be created out of non-matter particles such as photons, or even out of pure energy, such as kinetic energy). Force carriers are usually not considered matter: the carriers of the electric force (photons) possess energy (see Planck relation) and the carriers of the weak force (W and Z bosons) are massive, but neither are considered matter either. However, while these particles are not considered matter, they do contribute to the total mass of atoms, subatomic particles, and all systems that contain them.
How many quarks and leptons are there?

ANS: unanswerable

QUES: According to the Somali Economic Forum, the number of internet users in Somalia rose from only 200 in the year 2000 to 106,000 users in 2011, with the percentage continuing to rise. The number of mobile subscribers is similarly expected to rise from 512,682 in 2008 to around 6.1 million by 2015.
When did Somalia first get the internet?

ANS: unanswerable

QUES: Kerry received his second Purple Heart for a wound received in action on the Bo e River on February 20, 1969. The plan had been for the Swift boats to be accompanied by support helicopters. On the way up the Bo De, however, the helicopters were attacked. As the Swift boats reached the Cua Lon River, Kerry's boat was hit by a B-40 rocket (rocket propelled grenade round), and a piece of shrapnel hit Kerry's left leg, wounding him. Thereafter, enemy fire ceased and his boat reached the Gulf of Thailand safely. Kerry continues to have shrapnel embedded in his left thigh because the doctors that first treated him decided to remove the damaged tissue and close the wound with sutures rather than make a wide opening to remove the shrapnel. Though wounded like several others earlier that day, Kerry did not lose any time off from duty.
Where did Kerry's boat escape to safety?

ANS: Gulf of Thailand

QUES: The fiber is most often spun into yarn or thread and used to make a soft, breathable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated from 5000 BC have been excavated in Mexico and the Indus Valley Civilization in Ancient India (modern-day Pakistan and some parts of India). Although cultivated since antiquity, it was the invention of the cotton gin that lowered the cost of production that led to its widespread use, and it is the most widely used natural fiber cloth in clothing today.
To what date has cotton been dated?

ANS:
5000 BC