1. A signal is translated to cause muscle contraction
Answer;
Cell
Explanation;
-The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.
-Cell is the basic unit and building block of life. It is bound by a cell membrane, and possesses a nucleus which acts as its brain. Arachnoidiscus ehrenbergi is an example of diatoms which are unicellular, therefore it is a cell.
Chromosomes females have xx and males are xy
Gametes or sex cells.considered as haploid because they having a single set of impaired chromosomes.
so letter A,