ASSERTION AND REASON-Class 10 -Science-Biology

Assertion (A):   In xylem, vessels and tracheid’s are inter connected to form a continues system of water

 conducting channels.

 Reasoning (R): Root hair cells release ions.

 Choose the correct option

Assertion (A): Loss of water from aerial parts of the plant is known as transpiration.
Reasoning(R): During the day when the stomata are open, the transpiration pull becomes the major
driving force in the movement of water in the xylem.
Choose the correct answer

Assertion(A): CO2
diffuses out of amoeba when it starts accumulating to harmful levels in the cell.
Reasoning(R): In large organisms, diffusion alone is far too slow for adequate distribution of oxygen and
food.

Assertion(A): Fihses are called ammoniatelic animals
Reasoning(R): They contains nephrons which filter the blood and form the urine and large amount of
ammonia is found in fish excreta.

Assertion (A): Mammals are called ureotelic animals.
Reasoning (R): In mammals urea is the main excretory products so they are called ureotelic animals.

Assertion (A): Medullated nerve cells appears greyish in colour.
Reasoning (R): This neuron is not enclosed by myelin sheath; so it appears greyish in colour.

Assertion(A): The inner part of the cerebrum lying below the cerebral cortex is called white matter.
Reasoning(R): It consists of bundles of nerve fibres with myelin sheath giving the white colour.

Assertion(A): Less production of ADH causes Diabetes insipidus.
Reasoning(R):It helps in the reabsorption of water, producing concentrated urine in small quantity

Assertion(A): Aldosterone is called mineralocortoid.
Reasoning(R): Cortisone is called glucocortoid.

Assertion (A): Aldosterone maintains mineral metabolism.
Reasoning (R): Cortisone stimulates the breakdown of glycogen into glucose raising the blood
glucose level.

Statement - I: Sexual reproduction takes place by the combination of special reproductive cells called
‘sex cells’.
Statement – II: The sex cells are commonly known as gametes.

Statement - I: In sexual reproduction, a male gamete fuses with a female gamete to form a new cell
called Embryo.
Statement – II: The sex cells or gametes are also sometimes called germ cells.

Assertion(A):

 Sexual reproduction in plants take place in flower.

 Reasoning(R):

 Both male and female reproductive organs are present in flower itself.

Assertion (A):
Self pollination is known as autogamy.
Reasoning (R):
This is because pollen grains from the anther of a flower to the stigma of the same flower or another flower of the same plant are tranferred.

 Assertion(A): A geneticist crossed two pea plants and got 50% tall and 50% dwarf in the progeny.
Reason (R) : One plant was heterozygous tall and the other was dwarf.

Assertion(A) : Variations are seen in offspring produced by sexual reproduction.
Reason (R) : DNA molecule generated by replication is not exactly identical to original DNA.

Assertion(A) : Mutation is sudden change in the genetic material.
Reason (R) : Variation is useful for the survival of species over time.

Assertion(A): Mendel selected the pea plant for his experiments.
Reason (R) : Pea plant is cross-pollinating and has unisexual flowers.

Assertion(A): The sex of a child is determined by the mother.
Reason (R) : Humans have two types of sex chromosomes: XX and XY.

Assertion(A) : Evolution is an extremely slow process.
Reason (R) : New characters are accumulated in an organism during its lifetime.