Ethylene promotes senescence, which is the aging process in plants, leading to leaf drop and fruit ripening.

Plasma is the liquid component of blood that carries nutrients, hormones, and waste products throughout the body.

Saliva contains amylase, which begins the digestion of carbohydrates in the mouth.

The lymphatic system helps to remove excess fluid from tissues, returning it to the bloodstream and playing a role in immune function.

The primary function of the respiratory system is gas exchange, allowing oxygen to enter the bloodstream and carbon dioxide to be expelled.

The stomach secretes hydrochloric acid, which aids in digestion and creates an acidic environment for enzymes.

Bt cotton is a genetically modified crop that has been engineered to express a bacterial protein that is toxic to certain pests.

Carbon dioxide is a greenhouse gas that contributes to the greenhouse effect and global warming.

The Modern Synthesis integrates natural selection with Mendelian genetics, providing a comprehensive explanation of evolution.

All of the options listed (virus, bacteria, fungi) are considered living organisms in various contexts.

Nitrogen is a macronutrient that is essential for the synthesis of amino acids and nucleic acids in plants.

Plastic waste is a significant contributor to water pollution, affecting aquatic life and ecosystems.

Urbanization is a major threat to biodiversity as it leads to habitat loss and fragmentation.

Genetic Drift is a mechanism of evolution that involves random changes in allele frequencies, particularly in small populations.

Gene flow is the mechanism of evolution that involves the transfer of genetic material between populations through migration.

All of the options listed (natural selection, gene flow, and genetic drift) are mechanisms of microevolution, which refers to small-scale evolutionary changes within a population.

Electroporation is a method used to introduce DNA into host cells by applying an electrical field to increase the permeability of the cell membrane.

All of the listed methods can be used to introduce DNA into plant cells, each with its own advantages and applications.

Electroporation is a method used to introduce foreign DNA into host cells by applying an electrical field to increase the permeability of the cell membrane.

Ion pumps are a form of active transport that move ions against their concentration gradient using energy.

Bioremediation involves using microorganisms, such as bacteria, to degrade environmental contaminants like oil spills.

Organisms can be classified using morphological, physiological, and genetic methods.

Abstinence is a method of contraception that involves refraining from sexual activity to prevent pregnancy.

All of the mentioned methods are effective in controlling microbial growth in food.

Gene therapy involves inserting a healthy gene into a patient's cells to treat genetic disorders.

Wildlife sanctuaries are a method of in-situ conservation as they protect species in their natural habitats.

Vaccination is a key method for preventing the spread of infectious diseases by building immunity.

Insulin is produced using fermentation processes involving genetically modified bacteria.

Composting utilizes microbes to decompose organic waste into nutrient-rich compost.

Bioremediation is the process of using microbes to clean up contaminated environments.