Avecciene is a substance containing incomplete portions of a virus that produce an immune response when injected into the body

Which feature of a human community is similar to a niche in a biological community

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?

What will happen if two of the base pairs of the stand of the dna are switched