They are substances produces in the endocrine glands, which regulate many of the functions of the body, like growth, metabolism, and reproduction. They are very complex chemical substances.

It seems a strange name but some of these fishes really look like a hatchet or chopper. They are very thin fishes, flattened from side to side. The front half of their body is very deep and shaped like a blade. There are two groups of hatchet fishes, one that lives in the sea and one that lives in fresh …

You have probably been told about the huge masses of ice that exist at the north and south poles today. You may also h., have heard that thousands of years ago great tongues of ice stretched southward from the north as far as Britain and northern Europe, and that millions of years before many of countries of the southern hemisphere …

Each galaxy has billions of stars. Such galaxies are not uniformly spaced in the universe but exist in groups and clusters; a group containing up to 40-50 galaxies and clusters containing about thousands of galaxies. These along with isolated galaxies may form larger clusters known as galactic superclusters. These are the largest structures of matter found in the universe. Our …

Fossils are the petrified remains of living things. There are three types of fossil, and each type is useful in telling us how creatures lived millions of years ago. The first type of fossil is part of the body of the creature, usually the hard part of the body like the shell or the skeleton, which is preserved as it …

Fizeau’s fringes occur in interferometry. One of the most common methods used to test the flatness of a polished surface is by analysing the interference patterns formed when the surface is placed against another polished flat transparent surface. When two surfaces are fully in contact, a pattern of concentric dark and light circles is seen and these patterns (or fringes) …

In volcanoes, lava emerges through a pipe in the top of the mountain. Sometimes, lava also reaches the surface through long cracks in the ground, called fissures. In 1783, lava spilled out of a 32-km (20-mile) long fissure in Iceland and buried 565 square km (218 square miles) of land.

A fern is any one of a group of about 12,000 species of plants. Unlike mosses, they have xylem and phloem (making them vascular plants). They have stems, leaves, and roots like other vascular plants. Ferns do not have either seeds or flowers (they reproduce via spores). By far the largest group of ferns are the leptosporangiate ferns, but ferns …

Eddy currents may be defined as currents induced in a thick conductor when it is placed in a changing electric field. Consider a metallic block placed in a continuously changing magnetic field by keeping the block fixed and changing the magnetic field with the help of an alternating current. Due to the continuous change of magnetic flux linked with the …

Dendrimers are repeatedly branched, roughly spherical large molecules. The name comes from the Greek word “δένδρον” (pronounced dendron), which translates to “tree”. Synonymous terms for dendrimer include arborols and cascade molecules. However, dendrimer is currently the internationally accepted term. A dendrimer is typically symmetric around the core, and often adopts a spherical three-dimensional morphology. The word dendron is also encountered …