Natural depression on the earths surface

Why do we perceive objects as retaining their brightness under different lighting levels?

The activity of the modern sample is 1.10 bq . how long does that measurement take?

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits