Answer: False
Explanation:
Protozoans are not the organism that fix nitrogen for the plants. The organism that fix nitrogen to convert it into a form which can be used by plants are known as diazotrophs.
These are bacteria and archae that fix nitrogen gas found in the atmosphere into more usable form such as ammonia.
These organism can grow without any external source of fixed nitrogen. Example: Rhizobia and azospirillium.
Answer:
an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells, typically magnified several hundred times.A microscope is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisible to the eye unless aided by a microscope.
Answer:
Water distribution on Earth greatly affect settlement of population because water is a necessary item for the survival of living creatures. Without water there is no life. Availability of water increases vegetation and increases the beautification of the area and peoples are attracted to live there.
Those areas where plenty of water is available having maximum population while those areas where water is present in low quantity, the population is also low like deserts.
Answer: C) the genes of this phage were made of DNA.
Explanation: the experiment described above wherein a radioactively labeled bacteriophage was allowed to infect bacteria ultimately led to the conclusion that the genes of the bacteriophage under study were made of DNA (a biopolymer of deoxyribonucleic acid, which is a type of nucleic acid composed of four different chemical groups, called bases: adenine, guanine, cytosine and thymine). Simply put, the experiment shows that the genetic material of the phage is DNA.
