<span>Like the sporophytes of seed plants, those of ferns consist of stems, leaves androots. Stems: Fern stems are often referred to as "rhizomes", even though they grow underground only in some of the species.</span>
Buccinators are muscles in the cheek that help smiling.
Laris oculi are muscles helping close eyelids.
Orbicularis oris is a muscle that helps manipulate the mouth:
the correct answer is D. all the above are muscles that help facial expression.
Genetic variation occurs.
Mutations are not copied over and over again.
Asthma is a chronic disease of the lung that has been increasing at an alarming rate in industrialized countries around the world over the last few decades. Although considerable progress has been made in our understanding of the underlying pathogenesis of the disease, the exact causes of the increasing prevalence are unknown. Studies suggest that most asthma develops in early childhood and that environmental factors present early in life may be crucial in the development of disease. One potential explanation for the recent epidemic referred to as the "hygiene hypothesis" postulates that factors that have resulted in a reduction in exposure to microbial products and/or infections in the western world may be contributing to this rise in disease prevalence. As early life influences are known to play an important role in establishment of asthma, studies have focused on the interface between mother and child that occurs during gestation and through breastfeeding. In this regard, the body of evidence regarding the relationship between breastfeeding and asthma indicates benefit but with the potential for risk. While providing population-level protection from infections and atopy in infancy and early childhood, breastfeeding might also pose an increased risk of atopic asthma among children with asthmatic mothers.
All cells require enzymes<span> to survive and </span>function.Enzymes<span> are catalysts, which means that they make chemical reactions go faster, but are not changed by the reaction.</span>
