:
Experiment steps: 1 Mark each
Inference: 1 Mark
1) A plant is selected and destarched bykeeping it in darkness for 3 days. Pick a leaf and test it with iodine to confirm that the plant is starch free. It won't turn blue-black, which means it did not perform photosynthesis in the darkness and all the starch is used up by the plant.
2) Cover one leaf with black paper.
3) Expose the plant to sunlightfor a day.
4) After a day, test the leaf covered with black paper using iodine. It will not turn blue-black as it has not synthesised starch, while the other uncovered leaves will now turn black-blue on the addition of iodine.
Inference:Photosynthesis did not occur in the leaf covered with black paper confirming the essentiality of light for the synthesis of starch.

Answer: Option D. -> sun
:
D
The solar energy is captured by leaves and is stored in the plants as food. This food is consumed by animals. All animals, either directly or indirectly depend on plants for their nutrition. Thus, sun is the ultimate source of energy for all living organisms.

:
Differences: 1 Mark each
Examples: 1 Mark
S.No
Parasites
Saprophytes
1.
They grow on other
organisms and derive their nutrients from
them.
They obtain their
nutrition from
dead and decaying
organic matter.
2.
They take readymade
food from the host
plant.
They release digestive enzymes
into the surroundings and absorb the
digested food.
Examples
Cuscuta, orchids
Fungi, some bacteria

:
Rhizobiumbacteria thriving in the root nodules of leguminous plants are capable of nitrogenfixation. They are able to convert atmospheric nitrogen to the form usable by plants.

Answer: Option A. -> True
:
A
In the presence of starch, iodinechanges its color from brown to blue-black or purple.So, iodine can be used to test the presence of starch.

Answer: Option D. -> parasite
:
D
$\bullet$ Parasitic plants obtain nutrition from the host and in the process deprives the host of its valuable nutrients. An example of parasitic plant is cuscuta.
$\bullet$ Autotrophs are organisms which can synthesise their own food.
$\bullet$Heterotrophs feed on autotrophs for food.
$\bullet$Saprophytes absorb nutrients from dead and decaying organisms.

:
Explanation: 2 Marks
Examples + reason: 1.5 Mark each
Parasitic mode of nutrition is where an organism (parasite) lives on the body surface or inside the body of another type of organism (host). The parasite obtains nutrition directly from the body of the host and in turn harm the host. This type of nutrition comes under heterotrophic nutrition.
Examples
Cuscuta: It is a parasitic plant which develops special roots called haustoria. They are non-greenand they derive nourishment by using their haustoria to gain access to the food and water conducting tissues of the host plant.
Mistletoe is also a parasitic plant which derives nourishment by gaining access to the vascular tissue of the host plant. Similar to that in Cuscuta.

Answer: Option A. -> True
:
A
Algae contain chlorophylland can prepare their own food by the process of photosynthesis in the presence of sunlight, utilisingcarbon dioxide and water.

Answer: Option B. -> autotrophic
:
B
Thereare certain organisms which can make their own food and are called autotrophs. They utilise carbon dioxide and water in the presence of sunlight and chlorophyll and make their food in the form of glucose. This process is known as photosynthesis.

Answer: Option D. -> carbon, hydrogen and oxygen
:
D
Carbohydrates are made of carbon, hydrogen and oxygen atoms. These atoms are arranged together in an specific order to form carbohydrates.