Page 8 - 41. GLM P4 Sci BTR Answer Key (AK007)
P. 8

 Revision 9
             SECTION A

             1.      (3)      The germination of seeds is only affected by water, temperature and air.

             2.      (3)      The mass of seed leaves decreases because the amount of stored food decreases.
                              However, the seedling will start to develop true leaves to make food as the stored
                              food in the seed leaves decreases so that it can continue to grow.
                              [The young plant does not depend on seed leaves for food after day 6.]

             3.      (1)      A mango tree is a flowering plant. A flowering plant reproduces by seeds.
             4.      (3)      The roots appear first before the shoot to push the seed leaves to the surface of
                              the ground.

             5.      (3)      •  Animal X is a frog because it does not have 3 pairs of legs. A frog also has a
                               3-stage life cycle.
                              •  Animal  Y  is  a  mealworm  beetle  because  it  lays  eggs  on  a  leaf  or  a  rotten

             SECTION B
             6.   (a)   Q: young plant
                        R: adult plant

                  (b)   P. It does not have leaves to trap sunlight to make food yet, so sunlight is not needed.

             7.   (a)   Both have a 4-stage life cycle. / Both have the stage of larva.
                  (b)   The life cycle of a tick has the nymph stage but not in the life cycle of a beetle. /

                        The life cycle of a beetle has the pupal stage but not in the life cycle of a tick. [Any one]
                  (c)   The larva of the tick has 6 legs which is a characteristic of an insect. However, the adult
                        tick has 8 legs which is not a characteristic of an insect.

                  (d)   Yes. The young beetle moults at the stage of larva in the life cycle. Since the tick has a
                        stage of larva, the young tick will moult also.

             8.   (a)   Q. As the seedling obtained its food from the seed leaves before it can make its own
                        food, it caused the mass of the seed leaves to decrease.

                  (b)   The tightly-sealed lid prevented the seeds from having air to germinate.
                  (c)   The presence or absence of air
                        [The changed variable is also called the independent variable.]

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