Which of the following is true regarding active transport? Choose 1
А
It allows particles to pass easily between lipids in cell
membranes.
B
An input of energy is not needed for it to occur.
C
It moves particles from areas of high concentration to
areas of low concentration.
D
It occurs against the concentration gradient.​

Asample of the male sex hormone testosterone, c19h28o2, contains 3.88×10^21 atoms of hydrogen.(a) how many atoms of carbon does it contain? (b) how many molecules of testosterone does it contain? (c) how many moles of testosterone does it contain? (d) what is the mass of this sample in grams?

Which of these conditions most likely produces an unstable isotope?

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)