Update DateUnit
2023.10.29

Diversity

Which insect has no wings?
  1. silverfish
  2. millipede
  3. butterfly
  4. grasshopper
The ____ help(s) a fish to steer when it is swimming.
  1. eyes
  2. tail
  3. gills
  4. fins
Fish do you know?

Fish breathe through gills found under their gill covers. Mudskipper can survive out of the water for a few hours because it can retain water in its mouth and breathe through its skin.

Most fish have fins to help them swim, balance and steer their bodies in water.

A fish uses its tail or caudal fin to propel forward through the water. Its pectoral fin helps to **steer it **in different directions. Without its pelvic fin, the fish will have difficulty maintaining its balance in the water.

Most fish reproduce by laying eggs. However, some fish like the guppy, molly and swordtail, give birth to their young alive. ⚠ They are still fish, not mammals. ⚠ Apart from mammals, some fish also give birth.

The molly, swordtail and guppy are some species of fish that reproduce by ____.
  1. blowing bubbles
  2. giving birth to live young
  3. laying eggs
  4. asexual reproduction
answer
  1. giving birth to live young but they are still fish

Cycles

How can we break the life cycle of the Aedes mosquito so that it does not spread diseases like dengue fever to us?

​ A. Remove stagnant water in pails. ​ B. Keep gutters free of debris. ​ C. Boil the tap water before drinking.

  1. C only
  2. A and B only
  3. B and C only
  4. A, B and C
answer
  1. A and B only

​ A. By removing stagnant water in pails, you are removing the breeding sources for the Aedes mosquito to lay eggs.

​ B. Debris in gutters prevents the flow of water; this means that water is collected in pools in the gutters which will be good breeding places for mosquito to lay eggs.

Study the table below.

Each of the mealworms, P, Q, R and S, is at a different stage of growth. They are placed in four different containers. 10 g of food is placed in each container together with the mealworm at the start of experiment. The amount of food left in the containers was recorded after 3 days.

MealwormAmount of food left in the container (10g)
P8
Q6
R3
S10

Which mealworm is most likely to be in the pupal stage?

  1. P
  2. Q
  3. R
  4. S
answer
  1. S
Which of the following explains why moulting is necessary?
  1. The nymph has outgrown its old exoskeleton.
  2. It needs to change from a pupa to a larva.
  3. It needs to eat its old exoskeleton for nutrition.
  4. This increases its chances of reproducton.
answer
What factors are necessary for the germination of a seed?
  1. warmth and water
  2. air and warmth
  3. air, sunlight and water
  4. air, water and warmth
answer
  1. air, water an warmth
Roots have tiny structures called ____ to help take in water and mineral salts from the soil.
  1. tubes
  2. root hairs
  3. seed coats
  4. shoots
answer
  1. root hairs
What happens to the seed leaves when the plant is able to make its own food?
  1. Nothing will happen to them.
  2. They drop off from the plant to grown into new young plants.
  3. Their function is to make food for the plant too.
  4. They shrivel up and fall off.
answer

  1. The function of the seed leaves is to provide food for the seed to grow into a young plant before its true leaves appear. The seed leaves become smaller when the storage of food is slowly used up by the young plant as it grows. The seed leaves will finally shrivel up and drop off once the young plant has developed its true leaves to make food for itself.

    Referring to Everything You Need To Know About pg220. Stage two of life cycle of a bean plant.

    As the roots grow, a stem also appears. The bean uses the food in the seed leaves to grow.