Levi decides to examine the effect of fertilizer on the growth of tomato plants. he chooses four plants for his experiment and applies varying amounts of fertilizer to the three of them. he does not apply fertilizer to one plant over a 15-day period, the plants receive fertilizer on days 1,4,7,10, and 13. levi measures the height of all of his plants with a meterstick on days 3, 6, 9, 12, and 15. he also makes sure to hold all experimental factors constant except for the fertilizer. what is the independent variable in levi's experiment on tomato plants?
a. the days plant height was measured
b. the measurements of plant height
c. the days fertilizer was applied
d. the amount of fertilizer given to the plants

it's     c       this is a cell (b) with a nucleus (c) containing dna (a). the dna is organized into chromosomes (d). a section of the chromosome that codes for a trait is called a gene (e).

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.

links? do you have a link? i don't see anything?

i'd have to say the answer is probable the second option "the geosphere interacting with the atmosphere"