You decide to plant a garden in your backyard. you dig up a strip of grass in a sunny spot. when you have finished digging up the grass, but you haven't planted anything, you have created a(an) in the lawn.
a. ecological disturbance
b. new community
c. none of the answer options is correct.
d. ecological disturbance and a new community

The correct answer is a. ecological disturbance

Explanation:

Any event that disrupts the ecosystem by changing the structure of biotic communities and abiotic elements is called ecological disturbance. So ecological disturbance has a devastating effect on communities that like in that ecosystem.  

These disturbances can be natural like disturbance from tsunami, volcanic eruptions, landslide, flood, etc. Disturbance created by human activities comes under artificial ecological disturbance for example disturbance created by dams.

Here the disturbance is created by digging up the grass which changes the structure of biotic and abiotic elements of that ecosystem therefore it is an example of ecological disturbance.

the answer is b.) hydrogen bonds between bases.