सभी स्थिर पारिस्थितिक तंत्रों में किस प्रकार का पारिस्थितिक स्तूप (pyramid) हमेशा सीधा (upright) होता है?

Which statement describes the ecological disruption caused by invasive species in a forest ecosystem?

Which of the following processes describes the natural renewal of a forest ecosystem through seed germination or vegetative sprouting following a disruptive event?