To investigate the possible presence of introns in three newly discovered genes (X, Y, and Z), you perform an experiment in which the restriction enzyme HaeIII is used to cleave either the DNA of each gene or the cDNA made by copying its mRNA with reverse transcriptase. The resulting DNA fragments are separated by gel electrophoresis, and the presence of fragments in the gels is detected by hybridizing to a radioactive DNA probe made by copying the intact gene with DNA polymerase in the presence of radioactive substrates.
The following results are obtained:

Source of DNA Number of Fragments After Source Electrophoresis
Gene X DNA 3
cDNA made from mRNA X 2
Gene Y DNA 4
cDNA made from mRNA Y 2
Gene Z DNA 2
cDNA made from mRNA Z 2

(a) What can you conclude about the number of introns present in gene X?
(b) What can you conclude about the number of introns present in gene Y?
(c) What can you conclude about the number of introns present in gene Z?

Complete the sentences by matching the names of trees to the appropriate blanks. to do this, drag the names on the left into the appropriate blanks in the sentences on the right. match the words in the left column to the appropriate blanks in the sentences on the right. terms may be used more than once. make certain you have filled every blank with a term before clicking submit. 1. deciduous trees lose their leaves seasonally and include trees such as maple and elm. 2. conifer leaves are generally thin and needle-like, while seeds are contained in cones. conifers include cedar and pine. 3. evergreens are plants that maintain their leaves in all seasons and include trees such as cedar, elm, and pine. 4. hardwoods reproduce using flowers and have broad leaves; hardwoods include trees such as maple, , and cedar. elm returned you filled in 2 of 10 blanks incorrectly. mango trees are tropical broad leaf plants that maintain their leaves all year long. no credit lost. try again.

How can active reading strategies you? o a. they can you get into better physical shape. o b. they can you read fewer science articles. o c. they can you understand what you read. o d. they can you avoid reading altogether.

Climate warming trends allow plant and insect species to inhabit larger ranges. select the best answer from the choices provided