âI think weâve read every single book they have.â Mark chuckled. He still wasnât ready to put the children downâWill was hanging off of one hip, his hand on Markâs shoulder as he stoically looked down at Bridget, and Mabel had nuzzled into the crook of Markâs neck with a contented sigh.
Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule. These frustules show a wide diversity in form, but are usually almost bilaterally symmetrical, hence the group name.
All algae contain the pigment chlorophyll a . Diatoms are the only type of protist with shells. Both algae and plants form gametes in multicellular chambers called gametangia. Adverse environmental conditions induce individual cellular slime molds to aggregate, forming a colonial organism.