Q: Since europeans settled in the united states, about what percentage of topsoil has eroded away? Choices: - 42 percent - 10 percent - 25 percent - 33 percent A:
33 percent

(Question)
Q: What kind of bond consists of one sigma bond and one pi bond? Choices: - beta bond - covalent bond - ionic bond - double bond A:
(Answer)
double bond

Ques: Q: What medical emergency occurs when a blood clot blocks blood flow to part of the brain, causing death of brain cells? Choices: - cardiac arrest - epileptic seizure - heart murmur - stroke A:
Ans: stroke

(Q).
Q: Scientists found that the youngest rocks on the seafloor were where? Choices: - trenches. - mid - ocean sediments - mid - ocean glaciers - mid-ocean ridges A:
(A).
mid-ocean ridges

Ques:Q: The presence of what stratospheric gas layer decreases the frequency of skin cancer and other damaging effects of ultraviolet radiation? Choices: - plasma - cumulonimbus - smog - ozone A:

Ans:ozone

Ques: Q: How many types of glands does the dermis contain? Choices: - three - ten - six - two A:
Ans:
two