Which of the following steps of natural selection most relates to the passing on of traits from parents to offspring?

Which of the following is NOT one of the four most abundant elements in living things?

The smallest unit of an element that still retains the property of an element is

Potassium (K) has an atomic number of 19, and it has 20 neutrons. What is its atomic mass?

If life exists on Mars, what form is it likely to be?

The function of enzymes is to

For an element to have no charge, which must be equivalent in number?

Two studies were carried out to determine if children in daycare got more ear infections than children who stayed at home. The first study compared ear infection rates in 50 Canadian girls ages 1 to 2, half of whom attended daycare and half of whom stayed home. The second study compared ear infection rates in 1000 Swedish boys ages 3 to 4, half of whom attended daycare and half of whom stayed home. The results of these two studies differed greatly. Which of the following is LEAST likely to be the cause of such differences?

The periodic table displays the elements arranged according to

If you were to dissect a plant into smaller and smaller units, what is the smallest unit that would still be considered alive?