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.
Explanation:

Seed formation without fertilization in flowering plants involves the process of ---
A) APOMIXIS
<span>The best method used to prevent soil depletion would be contour farming.
In contour farming, the land is tiled in consistent elevation. Contour farming is efficient in reducing soil depletion because it can conserve rain water and reduce the erosion of soil.
If there is no contour farming in your option, then choose A. Adding fertilizer. </span>
1. The strength of magnetic field at A is 64 unit, then the magnetic field strength at B. is 256 units.
64 × 64 = 256 units.
2. If the strength of magnetic field B is 6 units then the strength magnetic field at A is 24 units.
which is 256 : 4 = 16 units.
Magnetic field is one of the two ways where the intensity of magnetic field is being expressed.
ANSWER:
After the volcanic eruption,lava cools down,vegetation reappears and microscopic plants grow,then the macroscopic plants and animals come at that place,then gradually the whole system builds and ecosystem recovers.
EXPLANATION:
Biodiversity means diverse population of plants and animals. After the volcanic eruption,both plants and animals donot exist because of high temperature and not suitable environment. With the passage of the time, the lava cools down and vegetation stars reappearing. First of all lichens and microscopic plants and after that macroscopic plants and animals come at that place.Thus suitable conditions reappear and gradually the whole ecosystem recovers.