Numerous barriers can prevent sperm from reaching and fertilizing the egg, this can be that the Sperm may be defected, or lack the required number of mitochondria needed to help move the sperm. Also, if sperm had already fertilized the egg, there is a change that takes place to the membrane surrounding the egg preventing further sperm from fertilizing.
1. spines to protect plants against animals seeking water.
2. A waxy coating on leaves to reduce water loss.
Answer: The question is not complete, here is the completed part gotten from other website.
Mammals and turtles are more closely related than are lungfishes and sharks. Hagfishes, lungfishes, and frogs have lobed fins.
Lancelets and coelacanths are more closely related than are chimaeras and coelacanths.
Organism (a) is a common ancestor of all chordates.
Descendants of organism (d) have limbs with digits. birds and ray-finned fishes have a notochord and jaws.
rays and frogs have vertebrae. organism (c) is a common ancestor of lampreys and lungfishes?
The correct options are;
Mammals and turtles are more closely related than are lungfishes and sharks.
Descendants of organism (d) have legs.
Rays and frogs have a vertebral column.
-Birds and ray-finned fishes have a notochord and jaws
Explanation:
This is because phylogenetic tree is a branching diagram that entails different evolutionary relationships that occur between organisms or biological species having common decent or ancestors and showing similar and differences in their genetic characteristics or traits. It shows how species evolved from their ancestors.
Pretty fast. Or maybe slow.
Answer:
Metales alcalinos
El grupo 1A (o IA) de la tabla periódica son los metales alcalinos: hidrógeno (H), litio (Li), sodio (Na), potasio (K), rubidio (Rb), cesio (Cs) y francio (Fr). . Estos son (excepto el hidrógeno) metales suaves, brillantes, de bajo punto de fusión y altamente reactivos, que se empañan cuando se exponen al aire.
Explanation:
