How are casts formed by decaying organisms? Organisms turn into rock over time.
Organisms leave carbon residue on a rock.
Organisms leave impressions in sediment that hardens into rock.
Impressions left by organisms are filled in with sediment that hardens into rock.

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

Once an egg cell is fertilized by sperm, the cell then, as the embryo develops, it receives nourishment and eliminates wastes by transferring substances from its blood to its mother's blood. a. becomes a fetus immediately and exits the womb b. begins to divide and implants itself in the wall of the uterus c. remains in the uterus without dividing for several months d. travels back to the ovaries until the fetus is developed

The diagram shows a chicken embryo and a human embryo