This thin layer surrounds all cells and controls what materials can enter or exit. A) chloroplast
B) nucleus
C) cytoplasm
D) cell membrane
E) mitochondria
F)Golgi body
H) ribosomes
I) vacuoles
J)cell wall
K) endoplasmic reticulum
L) lysosome

Explanation:

D) Cell memberane

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

cytokinesis is the splitting of a cell membrane to form 2 identical daughter cells. it's similar to mitosis as both cells have identical copies of dna and cytokinesis is a step in the mitotic cycle.