Which type of algae is known to aid in firmness and skin renewal?

The correct answer is Chlorophyta, commonly known as green algae. This type of algae is known for its high concentration of vitamins, minerals, and phytonutrients, which can promote skin health and aid in firmness and renewal. Green algae are rich in antioxidants that help to protect skin cells from damage, improve hydration, and enhance elasticity, contributing to a more youthful appearance. Moreover, the presence of chlorophyll in green algae can stimulate the skin's natural renewal processes, leading to improved skin texture and tone.

Each type of algae serves different purposes in skin care, but Chlorophyta is particularly noted for its rejuvenating properties that enhance firmness, making it especially beneficial in products aimed at combating signs of aging and fostering skin vitality.