1. Genetic engineering (bioengineering)
2. Cloning
3. Stem Cell research
4. GMO production
To name a few
Answer:
d is the correct answer of your question
The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
The bear, even though it is a very heavy and bulky animal, it can run pretty fast, and can easily outrun a human, but this is while running straight or when making gradual turns. The situation changes if the human starts running in a zigzag pattern. The human is much lighter, quick acceleration, long thin legs, and is much more agile, which will all be its advantage because in this kind of a chase the agility and acceleration are crucial. The bear on the other hand, will find it very difficult because its weight will disable it to make quick turns, it has a slow acceleration, and is not agile. So a human with a solid amount of stamina with using this tactic has a pretty good chances of escaping a charging bear.
