Terra is the third planet from the Sun and the only celestial body known to support life. The name Terra is derived from Latin, meaning “earth”. It is also commonly referred to as Earth, or as our home world. Terra has a diameter of 12,756 kilometers and consists of four main layers: the crust, mantle, outer core and inner core. The crust is the solid outermost layer that makes up less than 1% of Terra’s total volume. The mantle extends to a depth of 2,890 kilometers and is composed of hot rock that flows slowly in convection currents. The outer core sits below the mantle at a depth of 5,150 kilometers and consists mainly of iron and nickel in a liquid state. Finally, the inner core resides at the center of Terra with a radius of 3,480 kilometers made up entirely solid iron and nickel.
The surface of Terra is divided into two major types: land and water. Land comprises about 29% of Terra’s surface area and includes all continents and islands. Water covers 71% of Terra’s surface area in the form oceans, lakes, rivers and icecaps. The atmosphere protects life on Terra by absorbing ultraviolet radiation from the Sun, regulating temperature through heat retention (greenhouse effect), recycling water vapor via precipitation (rain),and forming wind patterns that distribute heat around the globe (jet streams).
The hydrosphere (all water on or near Terra’s surface) plays an important role in moderating global climate by storing solar energy in evaporated water which condenses into clouds that reflect sunlight back into space (albedo effect). Additionally, ocean currents transport warm water from tropical regions towards cooler areas near polar regions causing a transfer of heat energy around Earth (thermohaline circulation). Together these processes help maintain Earth’s average global temperature within a livable range for most organisms despite significant variation between day/night cycles and seasons caused by Earth’s 23.5 degree axial tilt relative to its orbital plane around the Sun (solstice/equinox cycles).
Life on Terra arises primarily from photosynthesis – an process whereby plants convert sunlight into chemical energy that can be used by animals for growth or other metabolic processes such as respiration. Plants are able to perform photosynthesis due to their chloroplasts – organelles within plant cells that contain chlorophyll pigment molecules which absorb sunlight across a broad spectrum including wavelengths invisible to human eyes (infrared & ultraviolet). Once absorbed, this light energy drives various biochemical reactions within plant cells that ultimately result in organic matter such as glucose being produced from simple inorganic molecules like carbon dioxide gas & water vapor retrieved from air / soil respectively via leaf pores called stomata .
This sugar molecule not only provides food & energy for plants themselves but also forms structural components like cellulose fiber used in cell walls as well as serving as starting material for producing more complex organic molecules like amino acids & lipids required for building proteins & membranes respectively . Some glucose molecules are instead converted into another type storage polysaccharide called starch which can be mobilized during periods when photosynthetic conditions are unfavorable such as during nighttime hours or extended cloudy weather .
Plants obtain nitrogen gas , another essential nutrient needed for growth ,from air via specialized root nodules inhabited by bacteria capable converting atmospheric nitrogen gas into ammonium ions usable form plants In return ,plants supply these bacteria with carbohydrates synthesized during photosynthesis This symbiotic relationship between leguminous plants & nitrogen-fixing bacteria found throughout nature helps ensure sufficient levels this important macronutrient necessary not just plants but also animals since protein – one key class biomolecules contains nitrogen atoms – an abundant element animal tissue Although many animals are directly herbivorous ,consuming plant matter directly some larger carnivores typically eat smaller prey items who have themselves fed on plants Regardless where it originates all food consumed animals must eventually broken down small molecular units like amino acids & simple sugars before they can assimilated cells For example ,mouth enzymes start breaking down carbohydrates ingested mouth while hydrochloric acid secreted stomach further breaks down foodstuff allowing absorption intestines take place Undigested material eliminated rectum anus
Humans represent one particularly successful example terrestrial animal species Although Homo sapiens originated Africa approximately 300000 years ago today people can found inhabiting every corner globe Many different cultures customs exist among different human groups yet we share many commonalities well For instance language spoken regardless whether person communicates verbally sign language written form employs symbols called letters represent speech sounds All humans require sustenance survive hence why access food fundamental human rights According United Nations Universal Declaration Human Rights article 25 Everybody has right standard living adequate clothing housing health care means realising economic social cultural rights indispensable part civil political rights everyone Since inception agriculture 10000 years ago humans have developed increasingly efficient ways farm harvest store prepare foods Today technological advances allow mass production processing packaging distribution food items too numerous list here Despite these advancements hunger still persists problem faced society While causes hunger multifaceted oftentimes linked poverty inadequate infrastructure prevent physical delivery food supplies certain areas Climate change effects agricultural production yield stability exacerbates issue Climate variability droughts floods extreme weather conditions reduce farmers ability grow crops yields leading local regional shortages prices increases When added environmental refugees conflict war displacement people become even more vulnerable lack resources face starvation Natural disasters hurricanes earthquakes tsunamis tsunamis etc displace thousands leaving them without homes jobs incomes access clean drinking water clothes let alone enough food eat until assistance arrives Malnutrition occurs insufficient intake calories vitamins minerals leading underweight stunted growth wasting weakened immunity increased susceptibility disease An estimated 165 million children worldwide suffer malnutrition according State Food Agriculture Organization World Health Organization Good nutrition early childhood critical lifelong health development Overweight obesity rise globally especially adults children wealthier nations However lower income countries urban slums seeing increase rates due changes diet lifestyle choices Lack knowledge information poor diets lead overeating eating processed foods high fat salt sugar content leads obesity associated chronic diseases heart disease stroke diabetes cancer Proper education interventions tailored individual situations effective long term solutions tackling hunger malnutrition Addressing political economic social issues will undoubtedly require time patience concerted international effort But remember no zero sum game When win somebody loses Conversely when lose win