Which of the following would make a good semiconductor? aluminum germanium gold concrete

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied

An architect plans to use solar energy to heat the next house he designs. what principle of absorption and infrared energy can be applied to the design of the new house? how could she apply to those principals?

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.