Mechanism of determining sex - Male or Female?

All over the world, plants and animals of different species from varied environments reproduce. One thing that is different across species is the mechanism that determines sex - male or female. 


In all mammals, including humans, male or female is determined by the fusion of XX or XY chromosomes.  Females have two X chromosomes while males have one X chromosome and one Y chromosome.  The offspring, whether be male or female is determined by the sperm cell, passed down from the male. If the male sperm contributes a Y chromosome, the result comes to be YX- male offspring, but if X chromosome, the result comes to be XX- the female offspring.
 
Birds are exactly the opposite of humans, in that the sex of their offspring is determined by egg cells rather than sperm cells. The females are homozygous, having two identical sex chromosomes, whereas males are heterozygous, having two different sex chromosomes. These chromosomes are labeled as W and Z. 
Cockroaches and some species of grasshoppers determine the sex of their offspring in a different way. There is only 1 type of chromosome: the X chromosome.  A female has two X chromosomes, while a male has only one. The gender of offspring is determined by whether or not the male passes on his chromosome.  If he does not, the offspring is male. 
In many other animals, chromosomes do not determine the sex of the offspring. For example, the sex of the offspring of the crocodile and turtle depends on the egg temperature during incubation. If the egg is incubated in high temperature, the offspring will be female. If it is incubated in low temperatures, then it will be male.
Unlike most other living species, most plants are hermaphroditic, meaning that they have both male and female sex organs.
For some plant species, genetic makeup determines gender; for others, environment plays a central role.


                                                                                                                                        Shreya Dahal

Influences of Advertisements on Teenagers

Advertisements have huge impacts on peoples' lives. Teenagers have more chances of being affected as they are still at the developing stage, both emotionally and physically. They tend to buy products advertised on television because they misunderstand how the product might affect them in the long run. In most cases it doesn’t work that way. 
Peers play enormous roles in teenagers’ lives. Friends affect the way they react to advertisements and to be more specific, the products they want to buy.  It's true that it is hard to balance out friends and family and, sometimes advertised products may lead to fights and money problems. Teenagers feel the need to "fit in" with the group, by purchasing the items their friends' possess. Sometimes this may lead to bullying and harassment.
FOOD. Ahhh……..Food is one of the most affective advertisements. I am sure that all of us have caught ourselves drooling over some mouth-watering junk that’s extremely harmful to our health. But when you actually go out and consume the product, it's not really as good as the advertisment is it? That’s exactly what advertisers are trying to achieve. They are using the media to try and get you to believe that their product is absolutely the best thing you could ever have.
One of the most common and effective ways that advertisers use to get you to buy the product is to feature a currently famous star in their advertisements. That way, teenagers really want to buy it because they think their idol is using the product.
In conclusion, advertisements can influence teenagers in many different ways, both directly and indirectly. So next time you see an apealling advertisement, it's good to think about it before you buy it.
- By Supriya Aryal