Given, 2Ca + O2 -> 2CaO, what is the 2 located in front of calcium called??

In pea plants, the allele for tallness (t) is dominant to the allele for shortness (t). in the cross between a tall pea plant and a short pea plant shown below, what is the probability that the resulting offspring will be tall? whats the percent

0.2348 grams of pbcl2 used to form 44.0 ml of solution.

How are isotopes of the same chemical element alike? how are they different?