Tag: modes of reproduction

• Water is an very important liquid present in the living world. Life has began in the water and the living organism cannot part from the water. They depend on water in major ways to continue their bodies major function.
• 70% of the animal body is made up of water. It helps in maintaining or maintains many functions of the body. Such as digestion and absorption of food which take place in the alimentary canal where the digested food is broken down with the help of water molecules into small absorbable component. Also after digestion some of the nutrients are absorbs along with water in the  digestive tract.
• As water itself talks long time to change its temperature compared to its surrounding it also helps in maintaining body temperature as the body is made up of 70% water and so the temperature of body is maintained. Where as the process of sweating and transpiration also release water to cool of the body when ever the temperature of body rises.
• Water is known to be an universal solvent as it can solve any polar solute such as salt, sugar, gases etc in the water, water molecule also form electrostatic bonds with ions who are partially soluble in pure water. Non polar solute are very poorly soluble in water.
• Also water is an important medium for reproduction. As the gametes that are required for the sexual reproduction cannot be produced with the water medium.
• Water works as the shock absorber for the brain and the spinal cord and protects them from the mechanical shock. As water is present in the fluid surrounding these organs.
  
• Therefore water is required for one function or the other in the body.
• Therefore the correct answer is option D 
  

Reproduction a process which is only possible by living organisms. So, reproduction exists as the defining property of living organisms.

Cleidoic eggs are those eggs, which have a protective shell, and are laid out of water. The shell is porous to air and may be flexible or calcareous (hard). The eggs contain all the food the embryo needs to develop into a hatchling. The significance of the cleidoic egg is that it enables reproduction out of and often away from water. The eggs of insects and birds, which is enclosed in a protective shell limiting the exchange of water, gases, etc. These type of eggs are found in reptiles, birds and monotremes. Therefore, non-cleidoic eggs will be found in fishes. Hence, option B is correct.

Most reptile eggs are leathery. It protects them when laid in holes, where they drop into contact with other eggs and it serves to make them more resilient, when covering the eggs with sand, dirt and other debris to conceal them. Hence, option B is correct.

Cleidoic eggs are those eggs, which have a protective shell, and are laid out of water. The shell is porous to air, and may be flexible or calcareous (hard). The eggs contain all the food the embryo needs to develop into a hatchling. The significance of the cleidoic egg is that it enables reproduction out of, and often away from, water. The eggs of insects and birds, which is enclosed in a protective shell limiting the exchange of water, gases, etc. These type of eggs are found in reptiles, birds and insects. Hence, option A is correct.

Centrolecithal egg, an egg in which the yolk is concentrated near the center of the egg cell, as is the case in many of the insects. Hence, it is correct match.
Megalecithal eggs are those eggs in large amount of yolk is present. Reptiles and birds are examples of this and not eutherian mammals, where alecithal egg is found.
Microlecithal eggs are those eggs in which small amount of yolk is present. Sea urchin, marsupials and amphioxus are examples of this and not reptiles, where megalecithal eggs are found.
Alecithal eggs are those eggs in which small amount of yolk is found. Mammals including humans are example of this and not birds, where megalecithal eggs are found.
Hence, option A is correct, which is only correct match out of given options.

• Cleidoic eggs are those eggs, which have a protective shell, and are laid out of water. 
• The shell is porous to air, and maybe flexible or calcareous (hard). The eggs contain all the food the embryo needs to develop into a hatchling. 
• The significance of the cleidoic egg is that it enables reproduction out of, and often away from, water. 
• The eggs of insects and birds, which is enclosed in a protective shell limiting the exchange of water, gases, etc. These types of eggs are found in reptiles, birds, and insects. Hence, option B is correct.

Enormous amount of yolk is present in megalecithal eggs and here yolk is several times greater than cytoplasm and yolk is concentrated in the interior of the egg and the cytoplasm is distributed as a thin layer on the outside of the yolk in centrolecithal eggs. These type of eggs is a characteristic of insects. Hence, option C is correct.

Mesolecithal egg are those eggs that has a yolk of intermediate size and strongly concentrated in one hemisphere. The young hatch at a later stage of development. It is a characteristic of lung fishes and amphibians likes frog. Hence, option B is correct.

Enormous amount of yolk is present in megalecithal eggs and here yolk is several times greater than cytoplasm. These eggs may be small or big. These types of eggs are characteristics of of teleost fishes, reptiles, birds. Yolk of egg is used for two purposes; supply of energy and synthesis of the products required for elaboration of the embryonic body.