Answer: The correct answer is-
C.They replaced carbon dioxide with oxygen in the atmosphere.
Cyanobacteria ( also known as blue green algae) is a large phylum of bacteria that is capable of synthesizing its own food using carbon dioxide and water in the presence of sunlight ( photosynthesis).
They contain a green pigment called chlorophyll that absorbs energy from sunlight and helps in the formation of food ( glucose). They release oxygen as a byproduct in the atmosphere.
As these organisms utilize carbon dioxide ( that is present in the atmosphere) to give oxygen in return, therefore, they affected early atmosphere of Earth by replacing carbon dioxide with oxygen.
Thus, option C) is the right answer.
Answer:
Option A, habits . . . environment
Explanation:
Good sleep hygiene include all the measures taken to enhance the quality and environment of a bedroom and to ensure a peaceful and calm sleep. Thus, in this way the environment of the bed room is enhanced along with assurance that good sleep habits are followed.
Sleep hygiene can help one to work on certain sleep habits such as –
a) Maintain consistency to go to bed
b) Do exercise
c) Peaceful and cherishing environment of bedroom.
Therefore, option B is correct
Answer: The correct answer is- A. Chromosome numbers vary widely.
Chromosome can be described as thread like structure that is composed of DNA ( deoxyribonucleic acid) and possesses genes ( segment of DNA coding for a particular protein) on it.
Eukaryotic cells ( such as plant cell, animal cell) have variable number of chromosomes.
For instance, human beings have 23 pairs of chromosomes whereas it is different in plants depending on the species.
Thus, A) is the right answer.
arachnoid
a fine, delicate membrane, the middle one of the three membranes or meninges that surround the brain and spinal cord, situated between the dura mater and the pia mater.
Answer:
During Anaphase stage
Explanation:
Meiosis is the type of cell division employed during gamete formation when each resulting gamete (daughter cell) has their chromosomal number reduced by half. Meiosis occurs in a two step division; Meiosis I and II. Meiosis I involves the separation of homologous chromosomes (similar but non-identical chromosomes received from each parent) while Meiosis II involves separation of sister chromatids (replicated chromosomes).
Alleles are present on the chromosomes which segregate or separate during the anaphase stage. Alleles received from each parent are separated in Anaphase I of meiosis I, which the identical replicated alleles are separated in anaphase of meiosis II.
