Tutor profile: Puneet K.
Subject: Environmental Science
What are endangered species?
An endangered species is a species of wild animal, plant or any other living organism that is in danger of extinction throughout all or a significant portion of its range . A species is considered threatened if it is likely to become endangered within the foreseeable future.
Why do we dream?
Our dreams mystify us and often leave us waking up confused, disoriented, frightened, or perhaps very satisfied. According to Freud, dreams represent unconscious wishes that we are afraid to express in our waking life. According to the activation-synthesis model, dreams are stories that we create out of the random stimulation that occurs in the brain while we sleep. The updated activation-integration-modulation (AIM) model proposes that dreams reflect the activity of regions of the brain active at a particular moment as well as the activity of particular neurotransmitters. This neuroscience explanation regards the stories we make up as reflecting, in part, our hidden desires, but they are not primarily the products of repressed wishes.
Why women live longer than men?
The main key why women live longer than men is gene mutation. DNA mutations in the mitochondria of men account for the differences in life expectancy between men and women. Mitochondria are cell organelles that provide the energy needed for cellular function. With the exception of red blood cells, all cells have mitochondria. Mitochondria have their own DNA, ribosomes, and they make their own proteins. Mutations in mitochondrial DNA are found to increase the rate at which males age, thus lowering their life expectancy. In contrast, these same mutations in female do not influence ageing. During sexual reproduction, the resultant offspring receive genes from both the father and mother. Mitochondrial DNA is only passed on via the mother. Mutations that occur in female mitochondria are monitored through genetic variation so that only favourable genes are passed from one generation to the next. Mutations that occur in male mitochondrial genes are not monitored so the mutations accumulate over time. This causes males to age faster than females.
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