Science [1 Mark Questions]

It is a monohybrid cross.
Example: when two hybrids tall Pea plants cross bred with eachother, they will produce three tall plants and one dwarf plant in F generation.

The presence of feathers on birds and dinosaurs shows that they are closely related to each other.

A, B, AB and O.

Dinosaurs and Archaeopteryx.

Due to the creation of variations, a species can adjust to the changing environment around it. And this promotes the survival of the species in the changing environment.
Example: The accumulation of ‘heat resistant’ variation (or trait) in some bacteria will ensure its survival even when the temperature in its environment rises too much due to a heat wave or some other reasons. On the other hand, the bacteria which did not have this variation to withstand heat would not survive under these circumstances and die.

Methane, Ammonia and Hydrogen Sulphide.

1. 23.
2. 46.

23.

Free Earlobes.

Tt.

Charles Robert Darwin.

1. Lizard (Agama agama).
2. Turtle (Chrysema Picta).

It is an example of monohybrid cross.

Gregor Mendel.

Genes.

Wild cabbage.

Sperm.

1. tt.
2. TT.

Black hair.

Planaria.

Those species which are now extinct are studied by studying their fossils which are found during the digging of earth.

Gametes.

False.

23.

46.

Pea plants.

The human beings who look so different from each other in terms of size, color and looks are set to belong to the same species because they can inter breed to produce fertile offsprings.

B.

Equal chance of having blood group O or blood group B.

Sea-water.

tt.

Snails: This indicates that sex is not determined genetically in some animals.

Homologous Organs.

The advantage of variation to a species is that it increases the chances of its survival in a changing environment.

Baby boy.

XY.

Human height and free ear lobe are the traits which show variation in humans.

46.

1. Wings of bird and wings of bat.
2. Wings of birds and wings of insects.

False.

False.

Sexual Reproduction.

Cabbage, Broccoli, Cauliflower, Kohlrabi and Kale.

Wild Cabbage.

The Origin of Species.

Gregor Mendel

TT.

The differences in the characters among the individual of a species is called variation.

In the F generation, all plants produced will be tall and in F generation three tall plantsand one dwarf plant will be produced.

Pea plants.