What calcium-rich formation builds the internal skeleton of echinoderms?

Previous pagenext pagepage 3 ofquestion 3 (1 point)which of the following consist of cells that do not have a nucleus? of the above

According to piaget, children have acquired the cognitive skill of conservation when they're able to a. understand that six ounces of liquid in a jar and six ounces in an elongated tube are equal. b. understand the viewpoint of other people. c. relate objects around them to their own needs. d. realize that the term heavy describes an object one way and the term big describes it another way. it is not b nor c. did this 2 x wrong..

In a cross between individuals of a species of tropical fish, all of the male offspring have long tail fins, and none of the females possess the trait. mating two of the f1 fish fails to produce females with the trait. explain the inheritance pattern of the trait.