The diagram shows a graduated slide, with divisions of 0.1 mm viewed using an eyepiece graticule. 0 10 20 30 40 50 60 70 80 90 100 Pollen grains were grown in a sugar solution and viewed using the eyepiece graticule. Diagram 1 shows the pollen grains at the start. Diagram 2 shows the pollen grains after four hours. 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 at start after 4 hours diagram 1 diagram 2 pollen tube What is the growth rate of the pollen tubes? A 5µmh–1 B 10µmh–1 C 5 mmh–1 D 10 mmh–1

Ascientist is investigating the effects of salinity on fish development. he places fertilized fish eggs in an aquarium that contains low salinity and observes their development. what factor would improve experimental design the most? place the fish eggs in the open ocean because that is the natural habitat include another aquarium that has normal salinity to compare to the low salinity aquarium include an aquarium that replaces salt with sugar to confirm that the effects are specific to salt grow algae with the fish eggs in order to provide adequate nutrients to the developing embryos