Another name for unicellular organisms that dominated Earth up to the Precambrian time is prokaryotes. The correct answer is D.
Answer:
Cell differentiation
Explanation:
Cell differentiation is common with multicellular organisms. It is the process by which a cell changes from one cell form to another. Cell differentiation makes the change from a zygote to a complex system with different parts.Cells which have been differentiated also becomes specialized. Complex multicellular animals and plants would not be in existence without specialization. This is because cells have specialized functions and each cell is very important to the survival of the organism.
1. Contraction
2. Actin
3. Tendons
4. Epidermis
5. Dermis
6. Acne
7. A nerve signal from the brain arrives at the intersection of the nerve and muscle cells and releases acetylcholine from the neuron. This triggers chemical changes in the muscle cell involving ions, including Ca2+. Calcium triggers the thick filaments, made of myosin, to attach to the thin filaments, made of actin, in the muscle cell, and the myosin pulls the actin toward the center of the muscle cell. ATP causes the release of the actin fibers, allowing the muscle to relax and the process to begin again.
For Penn Foster.
I think it is A because birds do help spread around the seeds hope i helped
