(a) The fruits which develop only from the ovary are called true fruits. The fruits which develop without fertilization are called parthenocarpic fruits. Banana is a fruit which is developed from the ovary without fertilization. Hence it is a true fruit and a parthenocarpic fruit.
(b) In most plants, after fertilisation by the time the fruit develops from the ovary, other floral parts degenerate and fall off. However, in a few species such as apple, cashew, strawberry, etc., the thalamus also contributes in the fruit formation. Such fruits are called false fruit.
(c) The seeds which have two embryonic leaves or cotyledons, are called dicotyledonous. The seeds which retain a part of endosperm as it is not completely used up during the embryo development are called albuminous seeds.
Castor seeds have two cotyledons and have a part of endosperm retained; hence they are dicotyledonous and albuminous.
Seeds offer several advantages to angiosperms –
• Seeds have a hard seed coat which provides protection to the young embryo.
• Since the seeds are a result of sexual reproduction, they generate new genetic combinations which lead to variations.
• The dispersal of seeds to far-off places which prevents competition among other members of the same species, thus preventing their extinction.
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