internal or external division

In multicellular organisms, the male gametes called the are produced by the male reproductive part and the female gametes called the eggs are produced by the female reproductive part. The male gamete of one individual fertilizes the female gamete of another individual to produce the zygote. Th..

There appear to be many structures that are similar because of the function they carry out and in their external appearance. However, these structures differ internally. Such structures are called analogous structures. For example, wings of bat and butterfly are similar in appe..

This theory blames the external or environmental forces that gradually damages the internal cells and organs leading to ageing. This theory includes Living theory Free radius theory Cross linking theory Wear and tear theory Theory of error catastrophe Somatic mutation theo..

Question: Which muscles are responsible for expiration? 1. external intercostal 2. internal intercostal 3. a and abdominal 4. b and abdominal Answer: ..

While the nervous system and endocrine system have their own features, they have a common method of communication. Both the systems release chemicals to communicate between cells. Together these two systems carry out a very complex process of maintaining a homeostatic (balanced) internal..

In human beings, sexual reproduction takes place. Sexes are separate and hence they are known to exhibit sexual dimporphism. Males have sex organs called the tetes while the females have sex organs called the ovaries. Even in the external appearance, males and females show differences. So..

> In humans, the eyes are directed forward and give binocular vision. Ears are sensory organs that function as the organs of hearing and the organs for equilibrium. It has receptors that convert the vibrations into nervous impulses that are transmitted via the auditory nerve to the brain. Each ear ..

Two patterns of growth are commonly seen in animals regarding the proportion of the various body parts. Isometric growth: In this growth pattern, an organ grows at the same rate as the rest of the body. As the organism growths, the size remains proportional. Examples: Fish and Locust Allometric gro..

The method used in the binary star system can be also used for planet-satellite binary system. This is possible because the planet and the satellite also revolve around a common centre of mass...

We know that the moon revolves around the Earth in a circular orbit and the Earth revolves around the sun in an elliptical orbi..