في الأشنات يوجد تكافل بين طحالب وحيدة الخلية وبين فطريات.
I. ما هو تأثير كل واحد من الكائنين في الأشنة على الكائن الآخر ؟

II. ما هو نوع التكافل في الأشنة ؟
أ. تكافل من نوع تطفلي
ب. تكافل من

the titanic would be the correct answer

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.