Answer;
I think it's d,possible spread of tropical diseases.
The complete statement made by Stephen Hawking is: "though much of its behaviour through out history, has been pretty stupid, and not calculated to aid the survival of the species."
If one looks at our history, there are some events that defy our capacity for logical thinking. One would think that, as we possess this capacity, we would be able to direct our decisions towards the survival of the human species.
However, in many cases greed and the desire for personal gain have taken precedence. One good example was the burning of the great library of Alexandria, one of the most significant libraries in the ancient world. This magnificent collection was lost during the siege of Alexandria, when Julius Caesar set on fire the ships in the harbor.
Another example is the atomic bomb, when science has been used to invent one of the most destructive weapons known to us. Atomic warfare is still a threat that may end all life on Earth.
Furthermore, the greed of some corporations has led to multiple ecological catastrophes that endanger not only other species but our own future as well. One example is the Bhopal gas leak in India, where in 1984, due to poor maintenance, the chemical plant released 30 metric tons of methyl isocyanite into the atmosphere.
Explanation:
vascular because it has spores
vascular because it has true roots
nonvascular because it has spores
nonvascular because it has true roots
A sacromere is a segment between two adjacent Z discs and are essential for the striated structure of the cardiac and skeletal muscles.
<u>Explanation:</u>
The Z disc is surrounded by the I band made of thin filament called actin. The I band is followed by the A band made up of thick filament called myosin. When the muscles contract the actin and the myosin become superimposed/overlapped.
The sliding filament model explains the contraction of the sacromere in which the Z discs move closer due to the overlapping of the thin and thick filaments. Thus the I band moves close to the A band which remain the same length as shown in figure.
