a rock sample contains 25 percent k-40 and 75 percent daughter product ar-40. if k-40 has a half-life of 1.3 billion years, how old is the rock?

Robert decides to go for a run when he gets home from school. As he begins running, his breathing rate starts to increase. What are the mechanisms that cause his breathing rate to increase? A.

Changes in the DNA sequence that affect the expression of genetic information are called A) infiltrations B) mutations C) replications D) transformations

When you hear the word invasive species what do you think of? How do you think an invasive species will compare to a native species in an area?

What are the 4 great lakes names

Which part of carol's nervous system gave her the strength to knock out the man's breath and run home faster than the wind?

In a typical data table, the first column of data represents the variable.

America has 36 total chromosomes in each body cell. After meerkat cells undergo the process of meiosis each gamete will have how many chromosomes

The doctor said "The child is you, simply the best of you." What does this mean?

2. What is an investigation? What is a demonstration? How are the different?

In animals, embryonic stem cells differ from adult stem cells in that