In fertilization processes of angiosperms, one sperm nucleus fuses with two other nuclei in the embryo sac to form an endosperm. what is an endosperm?

a- nutrient supply for the embryo

b- ovum

c- gametophyte

d- plant embryo in a protective covering

Based on the observation that only male crickets produce a song, you hypothesize that a male's song is a form of communication to potential mates. you set up a simple experiment to test this hypothesis. in the laboratory, you place a male snowy tree cricket in enclosure a, which is adjacent to enclosureb. in enclosure b, you place other insects, one at a time, and observe their responses to the male's song. the enclosures are designed so that the two insects being tested cannot see or smell each other, but sound is transmitted from enclosure a to enclosureb.

What is the membrane that sheath of schwann cell containing cytoplasm and nucleus that encloses myelin

Which does not describe a physical change happening to water? water evaporating in the sun water reacting with nitrogen gas water freezing and being broken apart with a knife water heating up on a stove