5. Expulsion of placenta should be within-
(A) 2 - 3 hr (B) 4 - 8 hr
(C) 6 - 8 hr (D) 10 - 12 hr

of those who start drinking before they're 15 will develop alcohol dependence

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

it enhances antibody production by t cells of the adaptive immune system.

hope i'm right

explanation:

not sure if this is what you'r looking for eubacteria and archaebacteria