Spermiogenesis: Transformation of spermatids into spermatozoa.
Spermiation: The process of release of spermatozoa from Sertoli cells into the cavity of sperminiferous tubules.

The protozoans like the Amoeba are considered as immortal because they divide by binary fission. During this type of asexual reproduction, there is distribution of the parent body into two daughter cells. The parental identity gets lost in the case of binary fission.

Haemophilia is a ***-linked recessive disease.
• More males than females are affected
• Affected sons are usually born to unaffected
mothers, thus the trait skips generations
• Approximately 1/2 of carrier mothers’ sons are affected
• It is never passed from father to son
• All daughters of affected fathers are carriers.

All these characters are being satisfied in this case. So the disease is a ***-linked recessive trait as evident from the pedigree chart analysis.

Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual disability, and characteristic facial features.

Dicotyledonous embryo has the following important parts:

• Embryonal axis
  • Main axis of the embryo which divides it into different regions
• Cotyledons
  • Seed leaves
  • Helps in Food storage
  • Provide nourishment to the developing radicle & plumule

Monocotyledonous embryo has the following important parts:

• Embryonal axis
  • Main axis of the embryo which divides it into different regions
• Cotyledon
  • Only one seed leaf exists
  • Termed as Scutellum
  • Located at one side of axis
• Plumule : Shoot tip
• Radicle : Root tip
• Coleorrhiza : Sheath enclosing radicle & root cap
• Coleoptile : Sheath enclosing plumule & a few leaf primordia

When animals such as bees, butterflies, moths, flies, and hummingbirds pollinate plants, it's accidental. They are not trying to pollinate the plant. Usually they are at the plant to get food, the sticky pollen or a sweet nectar made at the base of the petals.

Life processes are the vital processes carried out by living organisms in order to maintain and sustain life. Molecular movements are essential to carry out the various life processes. Thus the processes which together perform the maintenance job are called life processes. Energy required to carry out the different life processes, is obtained through the process of nutrition. A series of chemical reactions in the body are necessary to obtain energy. Oxidising-reducing reactions are some of the most common chemical means to break-down molecules. The process of acquiring oxygen from outside the body, and to use it in the process of break-down of food sources for cellular needs, is called respiration. In the case of a single-celled organism, no specific organs for taking in food, exchange of gases or removal of wastes may be needed because the entire surface of the organism is in contact with the environment. In multi-cellular organisms, various body parts have specialised in the functions they perform.
The basic functions performed by living organisms to maintain their life on this earth are called life processes. The basic life processes common to all living organisms are – Nutrition and Respiration; Transport and Excretion; Control and Coordination; Growth; Movement and Reproduction.
 

Tailor made means, growing plants for a specific purpose such as high yield, disease resistant etc.

Using biotechnological methods, the genetic modification has been done in plants to create tailor-made plants to supply alternative resources to industries, in the form of starches, fuels and pharmaceuticals.

The process of formation of megaspores from the megaspore mother cell is called megasporogenesis. Ovules generally differentiate a single megaspore mother cell (MMC) in the micropylar region of the nucellus. MMC a large cell containing dense cytoplasm and a prominent nucleus. The MMC undergoes meiotic division which results in formation of four megaspores.

The removal of fertile top-soil from land by wind or water is called soil erosion. Soil erosion does not occur easily where the land is covered by vegetations. Soil erosion is caused mainly by the large scale cutting down of forest trees and other plants. Large number of trees is cut down for obtaining wood for burning as fuel for building purposes and the manufacture of paper. When the forest trees and other plants are cut down then the top soil gets exposed and becomes loose which causes soil erosion.

The soil erosion could be prevented by preventing large scale cutting down forest trees and by afforestation of large number of plants and trees.

The bronchi are located in your upper chest and are made of smooth muscle lined with mucous glands and cilia, small hair-like organs that collect dust and other foreign matter. The bronchi and other major air passageways are protected by cartilage, which helps them to keep their shape. The muscular walls of the bronchioles do not contain cartilage like those of the bronchi. This muscular wall can change the size of the tubing to increase or decrease airflow through the tube.

Photooxidation produces a variety of oxidation products of crude and refined oils, such as, aliphatic and aromatic ketones, aldehydes, carboxylic acids, fatty acids, esters, epoxides, sulfoxides, sulfones, phenols, anhydrides, quinones, and aliphatic and aromatic alcohols.

DNA fingerprinting is a technique that shows the genetic makeup of living things. It is a method of finding the difference between the satellite DNA regions in the genome.

Any piece of DNA sample found at a crime scene can be analysed for the level of polymorphism in the non-coding repetitive sequences. After the DNA profile is traced, it becomes easier to find the criminal by performing the DNA fingerprinting for the suspects.

Apart from crime scenes, Fingerprinting applications also prove useful in finding the parents of an unclaimed baby by conducting a paternity test on a DNA sample from the baby.

The exine is made up of sporopollenin, which is one of the most resistant organic material. The intine layer is made up of cellulose and pectin materials. The exine is hard and hence protects the pollen grains during adverse conditions. Exine provide protection. The exine is developed through the contribution of the early microspore cytoplasm and the inner anther wall cell layer, the tapetum, which plays a dominant role in the synthesis and deposition of sporopollenin on the pollen grain outer surface.

Sporulation in the bacteria is the process by which a vegetative cell is converted to endospore. Endospores are formed during unfavourable conditions only by Gram-positive bacteria. The first step is the formation of axial filaments surrounding the nuclear material forming a spore septum.

Juvenile phase:

It is the period of growth in an individual organism after its birth and before it reaches reproductive maturity.

Spermatogenesis is the process of the production of sperms from the immature germ cells in males. It takes place in seminiferous tubules present inside the testes. During spermatogenesis, a diploid spermatogonium (male germ cell) increases its size to form a diploid primary spermatocyte. This diploid primary spermatocyte undergoes first meiotic division (meiosis I), which is a reductional division to form two equal haploid secondary spermatocytes. Each secondary spermatocyte then undergoes second meiotic division (meiosis II) to form two equal haploid spermatids. Hence, a diploid spermatogonium produces four haploid spermatids. These spermatids are transformed into spermatozoa (sperm) by the process called spermiogenesis.

The process of formation of microspores from a mother cell through meiosis is called microsporogenesis. The microspores, as they are formed, are arranged in a cluster of four cells- the microspore tetrad. As the anthers mature and dehydrate, the microspores dissociate from each other and develop into pollen grains.

Ophioglossum, which has the highest chromosome count of any known living organism, with 1,260 chromosomes. This fern has roughly 630 pairs of chromosomes or 1260 chromosomes per cell.