Which series of labels correctly identifies the
indicated structures in this sketch of a cell
viewed under a microscope?
plant cell
a. nucleus b. chloroplasts c. cell
o wall d. golgi apparatus e. vesicle
f. endoplasmic reticulum
a. large central vacuole
b. mitochondrion c. cell wall
d. chloroplast e. vesicle
f. endoplasmic reticulum
a. nucleus b. mitochondrion
c. plasma membrane d. golgi
apparatus e. lysosome
f. endoplasmic reticulum
a. large central vacuole
b. chloroplasts c. plasma
membrane d. mitochondrion
e. lysosome f. endoplasmic
reticulum

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".