What is shown in this illustration? a) sister chromatids with different genes b) homologous chromosomes with homozygous alleles c) homologous chromosomes with heterozygous alleles d) heterozygous chromosomes with homozygous alleles

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

Where does the esophagus lead to in a frog?

Trees with light brown bark dominate an ecosystem the ecosystem has populations of insects that thrive on the tree bark over time some insect species developed certain physical characteristics that them thrive on the tree bark these physical characteristics also the insects defend themselves from predators which insect species is probaly the species with the new physical characteristics?