Which of the following represents change to an ecosystem brought about by abiotic factors?
a.
the decrease in plant populations due to a decrease in the available water supply
b.
the increase in a predator population due to the increase in prey population
c.
the decrease in plant species due to herd grazing
d.
the extinction of a plant species due to bacterial infection

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 8 options: the cold balloon expands and rises. the warm balloon shrinks and sinks. the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the warm balloon expands and rises. the cold balloon shrinks and sinks.