Doctors try to remove tumors from the body to prevent it from spreading and affecting other parts of the body.
Answer:
Phytoplankton are essential for atmospheric and climate regulation.
Explanation:
Phytoplankton are autotrophs, they use solar energy, along with inorganic carbon and water to produce their own food source via photosynthesis. During photosynthesis, they also produce oxygen, integral for the planet's atmospheric composition.
At their large biomass, phytoplankton contribute to a majority of the oxygen used by consumers (most animals).
6 CO2 + 6 H2O + light → C6H12O6 + 6 O2
Carbon Dioxide + Water + Light Glucose + Oxygen
Along with fossil fuels, human agricultural practices have contributed large amounts of CO2 to the atmosphere, This causes global warming, a major environmental crisis- global warming also leads to landmass loss, biosphere disruption and reduces biodiversity in mass extinction events.
Phytoplankton carbon cycling produces organic matter which functions as carbon sinks in our oceans. Thus, as phytoplankton use large amounts of CO2, they help combat warming cycles, along with producing O2 in atmospheric and climate regulation.
Answer:

point mutation, change within a gene in which one base pair in the DNA sequence is altered. Point mutations are frequently the result of mistakes made during DNA replication, although modification of DNA, such as through exposure to X-rays or to ultraviolet radiation, also can induce point mutations
Answer: nucleotides and monosaccharides are both monomers of macromolecules (nucleic acids and carbohydrates)
Explanation:
The correct answer is option C, that is, the presence of the nuclear membrane.
Cyanobacteria is a phylum of bacteria that attain their energy via the process of photosynthesis, and are the only photosynthetic prokaryotes possessing the tendency to generate oxygen. As a prokaryote, they are devoid of the nuclear membrane.
Euglena refers to a single cell flagellate eukaryote. It comes under the class Euglenoidea. The species of Euglena are witnessed in salt water and in freshwater. Being a eukaryote, they possess nuclear membrane.