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.

Penguin: In penguin, the feathers present are mainly for the purpose of keeping the body of the animal warm. They can jump with the help of their feathers but cannot fly.

Wild cabbage.

• Charles Robert Darwin gave the theory of evolution in his famous book ''The Origin of Species''.
• The theory of evolution proposed by Darwin is known as ''The Theory of Natural Selection''.
• This theory suggests that the best adapted organisms are selected by nature to pass on their characteristics to the next generation.

Speciation may be defined as an evolutionary process, which involves the formation of one or more species from an existing species.

Pisum sativum (garden pea) is the scientific name of the plant on which mendel performed his experiment.

Sperm.

Genetics.

1. tt.
2. TT.

Black hair.

Planaria.

Paleontology is the study of fossils. Fossils ( palaeontological evidences ) are the remains of dead organisms preserved in sedimentary rocks or other substances that lived in the remote past.

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

Most DNA is located in the cell nucleus where it is called nuclear DNA, but a small amount of DNA can also be found in the mitochondria where it is called mitochondrial DNA.

Gametes.

23.

46.

Homo erectus was considered as the first human type species which has an origination in Africa.

Convex mirror is a spherical mirror has larger field of view in general (also depends upon the orientation). Otherwise cylindrical mirror which can give a view of its surrounding in 360 degrees.

All living things can be divided into two types of cells: prokaryotes and eukaryotes. Eukaryotic cells have a nucleus and other cell structures that are bound by a distinct membrane.
Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a plasma membrane. Features that distinguish a bacterial cell from a eukaryotic cell include the circular DNA of the nucleoid, the lack of membrane-bound organelles, the cell wall of peptidoglycan, and flagella.

Variation.

B.

Trait.

The scientific name given to human species is Homo sapiens.

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

1. Genetics is the mechanism by which variations are created and inherited.
2. Evolution is used for studying the development of new types of organisms from the existing ones.

Sea-water.

tt.

Elements of first group have one valence election each in their atoms.
All the elements of group 1 have the same valency of 1.

According to the evolutionary theory, formation of new species is generally due accumulation of variations over several generations. Variations help the organisms to adapt to the changes in environment and on accumulation of sufficient variations, new species are formed.

Gregor Mendel is considered a as the Father of Genetics. Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent.

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

Evolution is scientific term for variations and Genetics is the science that studies heredity.

Homologous Organs.

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome. Individuals having two X chromosomes (XX) are female; individuals having one X chromosome and one Y chromosome (XY) are male.