<span>A hormone doesn't determine the gender. Chromosomes do. But the female hormones are estrogen and progesterone and the male is testosterone.</span>
<span>Planaria have a huge regenerative power because of the presence of adult stem cells called neoblasts. If you cut Planaria into pieces, each piece can regenerate into a complete organism and that’s a form of asexual reproduction. Cells which are located on the wound site proliferate to form a blastema-mass of cell that will grow into a new organ. Those cells will differentiate into new tissues and regenerate the missing parts.</span>
<span>The similar thing is happening with starfish.</span>
If it's the first mammal on earth then it's a type of reptile not pretty sure the name and what it looks like but it's a type of reptile for sure even though generation to generation we Been evolve by different types of mammal but before they where all fish a type of fish idk yet though lol.
Nivel subatómico: lo integran las partículas más pequeñas de la materia, como son los protones, los neutrones y los electrones.
Nivel atómico: lo componen los átomos, que son la parte más pequeña de un elemento químico que puede intervenir en una reacción.
Nivel molecular: está formado por las moléculas, que se definen como unidades materiales formadas por la unión, mediante enlaces químicos, de dos o más átomos, como por ejemplo una molécula de oxígeno (O2) o de carbonato cálcico (CaCO3).
Espero te sirva