CBSE Class 12-science Answered

When alien species are introduced deliberately for whatever purpose, some of them turn invasive and cause a decline or extinction of indigenous species. One such example of invasive weeds is Parthenium commonly called carrot grass. Parthenium hysterophorus infests pastures and farmland, causing a significant loss of yield. In some areas, livestock and crop production, and even human health has been affected due to the invasive growth of Parthenium. The plant produces chemicals that suppress crop and pasture plants, and allergens that affect humans and livestock. It also frequently causes pollen allergies.