Acommunity in texas broadcasts public service announcements on tornado safety right before spring. why is this the most effective time to do so?
a)
it is the time of year when the temperature contrast is greatest between colliding polar and tropical air masses over the central united states.
b)
it is the time of year when the temperature contrast is the least between colliding tropical air masses over the central united states.
c)
it is the time of year when the temperature contrast is the least between colliding polar and tropical air masses over the central united states.
d)
it is the time of year when the temperature contrast is greatest between colliding tropical air masses over the central united states.

they each offer a fresh glut of resources to the organisms that can arrive and exploit them. as individuals and new species continue to appear, they actively and passively alter the environment. competition for shared resources increases, local abiotic and biotic conditions shift, and the relative abundances of species change accordingly. the process is called ecological succession, and it is one of the earliest and most well-known concepts in ecology.

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

a) carbon, hydrogen

b) carbon, hydrogen, oxygen, nitrogen

c) carbon, hydrogen, oxygen, nitrogen, phosphorus

d) sugar

e) amino acid

f) nucleotide