A. <span>Exposure to an antigen
Exposure to viruses and antigens led to the foundation of modern vaccination. Vaccination introduces an antigenic material that helps the ability of the immune system to adapt a specific pathogen, therefore leading to a long-term immunity.</span>
Answer:
1. adaption
Explanation:
Salmon have special adaptation behavior that allows them to live in both freshwater and saline water during their lives.
<u>Salmons are born in freshwater where they spend few months and then move to saline water. For laying eggs, they again move to freshwater because eggs are unable to survive in saline water due to a process known as osmoregulation.</u>
Moving from freshwater to ocean water, salmon adapt according to the environment for their survival.
Hence, the correct answer is "1. adaption"
Answer:
The spinal cord is divided into 31 segments that send nerve rootlets out into the body through intervertebral foramen. These neurons travel into the spinal cord via the dorsal roots. Ventral roots consist of axons from motor neurons, which bring information to the periphery from cell bodies within the CNS.
Explanation:
Hope this will help
Answer: Precipitation occur more frequently than evaporation over land.
Explanation:
Precipitation refers to the water vapour that fall from the atmosphere in form of rain, snow, sleet, freezing rain or hail. It delivers water from the atmosphere to the Earth. Precipitation occur more on the land than evaporation, most water that teaches the surface of the Earth fall back on the land and fill the inland water, rivers , storages,e.t.c.
Evaporation occur frequently in the ocean because it is expose to the sun and most water that is evaporated from the ocean fall back to the ocean as precipitation.
Answer:
Nitrogen thet cannot be used by organisms. C.
Explanation:
Free nitrogen is simply molecular nitrogen (N2). Nitrogen, in its molecular form, consists of two nitrogen atoms bound together with a tripple bond. Because it is very stable, N2 is typically nonreactive, and takes a lot of energy to break them apart. Among these are the amino acids necessary for life to begin and which are the building blocks DNA is made from. Basically, any nitrogen that is in an organic compound is considered “fixed” nitrogen and N2 is considered to be “free” nitrogen
