Efficiency is
a.
the percentage of energy lost to the surroundings as heat.
b.
the percentage of energy that is actually used to perform work.
c.
the entire amount of energy.
d.
the time it takes for half of the energy to be used.

Darrel conducted an experiment with the following procedure: fill two cups with ice water. place an uninflated balloon snuggly onto your left index finger. blow a little air into an identical balloon, and place it onto your right index finger. place both fingers into the cups of ice water. darrel noticed that his right finger felt warmer in the ice water than did his left finger. which of the following does the experiment show? a. air is a good radiator of heat. b. air is a good insulator of heat. c. air is a good conductor of heat. d. air is a good convector of heat.

Parthenogenesis is a type of reproduction that does not require a mate. it’s rarely seen in birds and higher vertebrates. parthenogenesis involves the formation of a zygote. but this zygote is formed without fertilization. in parthenogenesis, in the absence of a male gamete, the ovum develops directly in the zygote.

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic