Microeconomics I don’t understand

Where do homologous chromosomes exchange genetic material through crossing over?               a.  chlorophyll    b.  centrosomes    c.  centromeres    d.  chiasma

20 points asap! question 1 - in your own words, explain the scientific evidence that supports the plate tectonic theory. question 2 - in your own words, explain why the geological structures in florida are different from the geological structures in colorado.

Plz genetic engineering can be applied to many fields including medicine and agriculture. which of the following is a medical application of genetic engineering? a. giving crop plants recombinant dna so that they would be resistant to herbicides. b. examining a persons pedigree to determine whether they can carry a gene for a genetic disease. c. analyzing a persons dna to see how closely they are related to another person. d. certain genes into bacteria so that they will produce a needed medicine.