Light speed, or 300,000 kilometers a second, might seem like a speed
limit, but this is just an example of 3 + 1 thinking – where we still
haven’t got our heads around the concept of four dimensional space-time
and hence we think in terms of space having three dimensions and think
of time as something different.
For example, while it seems to us
that it takes a light beam 4.3 years to go from Earth to the Alpha
Centauri system, if you were to hop on a spacecraft going at 99.999 per
cent of the speed of light you would get there in a matter of days,
hours or even minutes – depending on just how many .99s you add on to
that proportion of light speed.
This is because, as you keep
pumping the accelerator of your imaginary star drive system, time
dilation will become increasingly more pronounced and you will keep
getting to your destination that much quicker. With enough .999s you
could cross the universe within your lifetime – even though someone you
left behind would still only see you moving away at a tiny bit less than
300,000 kilometres a second. So, what might seem like a speed limit at
first glance isn’t really a limit at all.
To try and comprehend
the four dimensional perspective on this, consider that it’s impossible
to move across any distance without also moving through time. For
example, walking a kilometer may be a duration of thirty minutes – but
if you run, it might only take fifteen minutes.
Read more at: <span>https://phys.org/news/2011-10-light-speed.html#jC</span>
Periodontist is the term you're looking for
Answer:
b, d, and f
Explanation:
The transition from aquatic lifestyle to land posses some problems to plants; these include;
- <em>Water conduction and food distribution problem</em>
- <em>Desiccation problem</em>
In order to firmly establish in the terrestrial environment, <u>plants need to be able to obtain the water necessary for their metabolic activities and be able to distribute manufactured food from the various sources of production to other parts of the plant body.</u> This is overcome by the development of conducting tissues in the form of phloem and xylem. The xylem is used to conduct water from the root to the body of the plant while the phloem is a tissue used to conduct manufactured food from the point of manufacturing round the necessary parts of the plant.
<u>Plants also face the problem of heat and the risk of desiccation on land</u>. The development of waxy cuticle takes care of this problem. The waxy cuticle acts as an insulator on leaves and other organs of the plant and thus protect them from desiccation.
Correct options: b, d, and f
Answer:
ATP
Explanation:
(adenosine triphosphate) Its a chemical enegry teh cell uses.
