Answer:
Until recent history,extinctions have always happened gradually and on a small scale.
Explanation:
Extinction occur when environmental factors like natural disaster,habitat fragmentation,over exploitation,global change don't favor the survival of species thus gradually leads to extinction of species.
Some times human activity becomes the major problem for extinction.More over,poor reproduction,decline in population number and genetic inbreeding also leads to extinction.
99% of all species that exist on earth become disappeared.
Evolution leas to speciation which leas to formation of new species but species become extinct when they are unable to survive against competition.
<span>d. sporangia.
is a structure that can be found in unicellular and multicellular organisms that encloses spores. Organisms that form sporangia in their life cycles are plants, fungi and algae among others.</span>
Answer: Hi I have the answer to your problem!
Explanation:
Cardiovascular exercise is any vigorous activity that increases heart rate and respiration and raises oxygen and blood flow throughout the body while using large muscle groups of the body repetitively and rhythmically. So your answer is A.
