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.
Smoking can cause cancer and then block your body from fighting it: Poisons in cigarette smoke can weaken the bodyâs immune system, making it harder to kill cancer cells. When this happens, cancer cells keep growing without being stopped. Poisons in tobacco smoke can damage or change a cell's DNA. DNA is the cell's instruction manual that controls a cell's normal growth and function. When DNA is damaged, a cell can begin growing out of control and create a cancer tumor. Doctors have known for years that smoking causes most lung cancers.