Experiment 18 — The Life Cycle Puzzle

Topic: Biology · Class 8 · Reproduction in animals; metamorphosis

Aim: Put the four stages of the frog life cycle in the correct order.

Daily: A silkworm’s metamorphosis gives us silk; a mosquito’s means that emptying standing water stops malaria and dengue before the adults ever fly.

Question: A tadpole breathes through gills. When does it develop lungs?

Exp: Lungs and legs develop together as the tadpole changes into a frog.

Question: Fusion of a sperm and an egg is called…

Question: Animals that lay eggs are called…

Exp: Viviparous animals give birth to young ones.

Question: Hydra reproduces asexually by…

Exp: A bud grows and detaches as a new individual.

Question: Emptying standing water prevents malaria because…

Exp: Breaking the life cycle is the most effective control.

Question: A 60 N force acts on an area of 0.3 m². The pressure is…

Question: Pressure at the bottom of a liquid depends on…

Exp: P = hρg; shape is irrelevant.

Question: Which friction is smallest for the same surfaces?

Exp: This is why wheels and ball bearings are used.

Question: An alarm inside a jar becomes inaudible as air is pumped out because sound…

Exp: A vacuum carries no sound.

Question: The leaves of a charged electroscope spread apart because…

Exp: Both leaves carry the same charge.

Question: Two mirrors at 45° form how many images?

Question: In electroplating, the object to be plated is the…

Exp: Positive metal ions travel to the negative electrode.

Question: Covering a burning candle with a jar removes…

Exp: The flame exhausts the sealed air.

Question: Non-metal oxides dissolved in water are usually…

Exp: Metal oxides are basic instead.

Question: Zinc displaces copper from copper sulphate because zinc is…

Exp: A more reactive metal displaces a less reactive one.