Suppose a hard frost in southern Florida wipes out nearly all of a population of plants. Even though the plant population recovers in numbers after a couple of decades, the genetic variation within that population remains much reduced. Which is the most likely cause of the diminished genetic variation?

Which of the following groups possess xylem?

Members of the phylum ____________ characteristically have bodies with three distinct sections: mantle, visceral mass, and foot.

At which step in the diagram are gametes being formed?

The sporophyte of a vascular plant is nutritionally _______; the sporophyte of a nonvascular plant is nutritionally _______.

Which of the following groups has a water vascular system?

An unknown organism can be identified as a fungus if it

Cytochrome-c is a protein found in most organisms. The amino acid sequence of this protein varies between species. The numbers of differences in the amino acid sequences of this protein between three species of chordates A, B and C are shown in the table above. Based on this evidence, the phylogenetic tree that best represents the possible evolutionary relationships between the three species is:

_______ are not classified as a gymnosperms.

When an isotope releases gamma radiation the atomic number