There's been a lot of bad news for polar bears recently. In 2007, for example, scientists reported that if global warming continues unabated, the population could drop two-thirds by 2050.
I think it’s A. hope this helps
Answer:
organisms that have more favorable traits tend to leave more offspring ... improved fitness of certain individuals in the population that allows for survival and reproduction. ... Based on H-W conditions, five major causes of evolution: ... factors that prevent organisms of two species from producing vigorous, fertile offspring
Explanation:
<span>Letter A is the answer. Almost all plant cells have single large central vacuole. These large central vacuoles of the plant cells are filled with water and can take over 80% of its cell volume. This is surrounded by a single membrane called tonoplast. The role of the central vacuole is maintaining the plant cell's pressure.</span>