Compute the age of a basalt rock sample from the Moon containing 6 grams of Uranium-235 (parent isotope) and 42 grams of Lead-207 (daughter isotope). This rock is from a complex crater flooded with lava. The half-life of Uranium-235 is 704 million years.

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

The influenza virus cause the flu, but not other diseases. why?

Which of the following is not a defining characteristic of plants?