The four limitations are
1.It's often impossible to repeat trials on the same subjects.
2-Subjects may report an inaccurate medical history.
3-It can be difficult to control all possible variables.
4-It's impossible to come up with testable scientific questions for human subjects.
Research involving human beings is ultimately necessary for improvements in human health and welfare. Any results about healthy physiology, illness causes, treatment effectiveness, learning, or behavior must be verified by carefully controlled investigations involving human participants. Sadly, not all human research have been valid and beneficial. It is possible to harm people in the name of research. The most well-known instances happened in Nazi Germany. Investigations conducted after the war found several crimes, including experiments in which participants were submerged in extremely cold water to determine how long it would take them to pass away from hypothermia.
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ANSWER:
Problem faced include; habitat loss and degradation, disease outbreak, invasive species, pollution, over‐exploitation/overfishing, climate change etc.
EXPLANATION:
Problem:
Habitat loss and degradation, disease outbreak, invasive species, pollution, over‐exploitation/overfishing, and climate change are notable problems experienced by freshwater and marine fishes.
Solution:
Anthropogenic activities and stressors that rapidly threaten freshwater and marine fishes are curbed through legislation and other means to prevent extinction of fishes.
Through conservation programs that plans for individual species to more species of entire faunas of a particular location also boost population size and prevent hunting of threatened or endangered species in both realms.
Overtime, genetically modified fishes which can develop resistance to diseases are introduced to the realm.
Moreso, waste channels through which pollutants gets into the water bodies are well-treated for safety of fishes.
Nonpoint source so your answer would be B.
D. it is breathed out of the body by the lungs
It then enters the atmosphere and can be used by plants in photosynthesis to produce oxygen and glucose. Hope this helped :) if it did, please let me know by marking this answer as "brainliest!"
Answer:
Adaptations to a common environment and examples of convergent evolution
Explanation:
Convergent evolution is a process by which two independent and phylogenetically separated organisms, get to develop similar structures or behavior to survive. These structures make possible a better performance in a similar environment. These organisms are morphologically or ethologically similar in their whole bodies or just in parts.
Convergent evolution occurs in different phylogenetic branches independently from each other. It results from the need of different organisms to adapt to a similar environment and to solve a problem from that particular ecological niche. Ecological pressures acting on them might be similar, modeling the organisms´ phenotype. Each evolutive branch ends by developing the same structures, which they both find effective in their environment.
In the exposed example, Ichthyosaurs (reptile) and fishes are separated species on evolutive time, corresponding to different phylogenetic lineages. Both of them inhabit the same aquatic environment. Pressures of the habitat acted on them and modeling their phenotypes. These species need to adapt to living in water, moving, feeding, scaping, chasing, etc. So both species arrived at the same solution. They developed dorsal fins and tails, which are important to stabilize the body in the water while swimming, making it more hydrodynamic and getting to propel better.
