The exchange of segments of DNA between members of a pair of chromosomes during Meiosis... a) is called crossing
b) ensures that variations within a species never occur
c)acts as a source of variations within a species.
d)always produces genetic disorders

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

Question#29: why does the tropical ocean have a greater temperature range than the temperate ocean?

Select the correct answer. tay-sachs disease is caused by a mutation in the hexa gene located on chromosome 15. tay-sachs follows an autosomal recessive pattern of inheritance. with the of the diagram, identify which of the offspring will be an unaffected carrier. a diagram showing the genes of parents who are carriers of tay-sachs disease a. a, b, and c b. b and c c. a and d d. a e. d