(a)(i) Hydrosphere is the aquatic portion of the biosphere or life supporting living world or earth.
(ii) Examples of hydrosphere are: Lake, Pools, Spring, Oceans, Ponds, Oasis, Rivers, Streams, Manny.
(b)(i) The first law of thermodynamics states that energy can neither be created nor destroyed. The second law of thermodynamics states that in any conversion of energy from one state to another, there is always a decrease in the amount of useful energy.
(ii) Using the second law of thermodynamics, the energy flow across trophic levels can be explained as follows:

The transfer of energy between trophic levels is not 100%. That means it is not completely transferred.
Successive levels have less of useful energy and support fewer organisms.
Primary producers/plants have the highest amount of energy and when herbivores feed on plants, the energy level is reduced.
When carnivores consume the herbivores the energy level is further reduced.

(c) (i) Local biotic communities and the state each is found in Nigeria are:

Local biotic community	State
Tropical rainforest .Southern Guinea SavannaNorthern Guinea Savanna Sahel Savanna Mangrove/Swamp/Estuarine	Edo/Delta/Ondo/Imo/Abia/Lagos/Anam bra/Rivers/Bayelsa/Akwa-IbomEnugu/Kogi/Benue/Kwara/Oyo/Ebonyi/Osun/Ekiti.Plateau/Kaduna/Bauchi/Niger/Taraba/Adarnawa/Kano. Borno/Kastina/Sokoto/Yobe/Kebbi/Zamfara/Kano/Jigawa.Delta/Cross River/Rivers/Akwalbom/Bayelsa/Ogun/Lagos/Ondo.

(ii) Factors affecting marine organisms are: Temperature, Salinity, Pressure, Turbidity/light penetration, Dissolved oxygen, Density of sea water, PH/hydrogen ion concentration, Waves /up-welling of water, Current and Tides.
(iii) Adaptive features of sea weeds are;
(1) Possession of chloroplast/photosynthesis
(2) Absence of lignified tissue which makes them flexible and able to withstand wave actions
(3) Possession of hold fast for firm attachment to substratum or rocky surface
(4) Body covered with mucilage to reduce desiccation during low tide or on exposure
(5) Possession of air bladders for buoyancy.