Can someone help please

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

Many kangaroo rats live in the sonoran desert of the southwestern united states. they have a variety of adaptations for living in the desert. under which circumstance would the kangaroo rats of the sonoran desert be most likely to develop new adaptations by natural selection?

Select the star life cycle that is accurate