Non-vascular plants include two distantly related groups: 1  Bryophytes-Bryophyta (mosses), Marchantiophyta (liverworts), and Anthocerotophyta (hornworts). 2  In these groups, the primary plants are the haploid gametophytes, with the only diploid portion being the attached sporophyte, consisting of a stalk and sporangium. In these groups, the primary plants are the haploid gametophytes, with the only diploid portion being the attached sporophyte, consisting of a stalk and sporangium. 2  Because these plants lack lignified water-conducting tissues, they can't become as tall as most vascular plants. 3  Algae-especially the green algae.
It is possible that welders are at greater risk of developing skin cancer than the general population, but there is a dearth of well designed studies in this area. The only major study of the relationship between arc welding and skin cancer risk did not reveal an increased incidence of skin cancer in welders.
How smoking causes lung cancer. Doctors believe smoking causes lung cancer by damaging the cells that line the lungs. When you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately. At first your body may be able to repair this damage.he two general types of lung cancer include: 1  Small cell lung cancer. 2  Small cell lung cancer occurs almost exclusively in heavy smokers and is less common than non-small cell lung cancer. 3  Non-small cell lung cancer.