Because they want to know the existence of aliens
Answer:
chemicals are dumped into lakes and rivers
Explanation:
all the other choices are results of cutting down trees
bro this is so easy,
if to animals fight, the one more adapted, prepared or psychically built will win will the weaker one lose and die, which is natural selection at its finest.
I believe the increase in blood pressure is limited by the Vasodialtion that causes arterial diameter to increase in the exercising skeletal muscle.
Vasodilation causes increase in blood flow due to decrease in vascular resistance. The resistance produced mainly in the arterioles which is known as the systemic vascular resistance or the peripheral vascular resistance. The cardiac output is the function of heart rate and stroke volume and must be always on check.<span />
Complex organisms need cells that can perform many different functions. they need to be supported on a cellular level. Without specialized cells you they won't be able to perform different functions.