Ask Mr Brain...all will be explained

PUBLISHED : Wednesday, 23 June, 1999, 12:00am
UPDATED : Wednesday, 23 June, 1999, 12:00am

Are there more insects than people in the world? CAROL Yuen Long Merchants Association Secondary School There are many more insects than people in the world.

Insects are found in almost every imaginable habitat, and are the most numerous and diverse animals on earth.

Scientists have named about a million insect species, and some believe there may be 10 million more species waiting to be identified. And that's just the number of species. Imagine how many of each species there are! According to the United States Bureau of the Census, the total population of the world is 5,992,894,928. Insects outnumber us by probably millions, if not billions.

Insects not only have the ability to survive in the harshest of environments but they also reproduce at a much higher rate than humans.

Unlike humans, insects produce a large number of offsprings at a time.

Insects reproduce by laying eggs, and usually a group of eggs is laid at a time. Therefore, the insect population grows at a much faster rate than the human population.

Many insects have complex life cycles and go through several stages of growth before they become adults.

Some insects undergo a dramatic change called complete metamorphosis, while others experience a gradual transformation known as incomplete metamorphosis.

Why is the sea blue? ANNIE Yuen Long Merchants Association Secondary School Oceans cover three-quarters of the Earth's surface and are as diverse as they are large. The seas are an inter esting and little understood world full of fascinating creatures. It is a self-containing world with a complicated food chain.

Many organisms in the sea have adapted to extreme and unusual conditions.

Everyone knows the sea is blue, but no one can provide a concrete answer as to why. We all know that sea water is actually colourless. There are several theories which attempt to explain why the sea is usually blue.

One theory says that it's the reflection of sunlight, or solar radiation, that makes the sea look blue.

Some scientists believe that when sunlight hits sea water, part of the white light is absorbed and part is reflected.

White light is composed of different shades (all the colours in the rainbow). Sea water does not absorb blue light, so the blue light is reflected outwards.

Other scientists believe that suspended matter in the sea is responsible for its blue colour.

Significant sunlight can only penetrate 100 metres into the ocean. Since sea water is quite transparent, about five per cent of sunlight penetrates to a depth of about 80 metres. But if there is a significant amount of silt, algae or other matter in the water, the penetration depth can be reduced to 50 metres or less.

There is really one big ocean in the world.

You can sail in a boat in every 'ocean' and 'sea', which means they are all connected.