Answer:
It prevents harmful substances from entering a cell.
Explanation:
Answer: Only options A, B, C and D are true statements
A) One sperm fuses with an egg while the other sperm fuses with the polar nuclei.
B) It results in the formation of a diploid embryo and triploid endosperm.
C) Both sperms involved in double fertilization form within the same pollen tube.
- The diploid nucleus resulting from the second fertilization undergoes meiosis to form the endosperm.
Explanation:
Double fertilization is a process that occurs in only flowering plants. It involves the following:
- A pollen grain produces TWO male gametes
- one male gamete fertilize the egg to form a zygote that is DIPLOID (with two basic sets of chromosomes)
- the second male gamete fuses with another cell named POLAR NUCLEI, to form endosperm (the food storing tissue) in the seed. The endosperm formed is TRIPLOID ( it has three sets of chromosomes), having undergone reductive division - meiosis
Thus, the options A, B, C and D are true statements
Oranges are the best source of vitamin c
Answer:
A. Cell
B. Organ
C. Tissue
Explanation:
cell: The smallest unit of life capable of independent reproduction. Generally contains nucleic acid, cytoplasm, a cell membrane, and many other proteins and structures.
organ: A structure made of different tissues that work together to perform physiological functions.
Tissues: A group of similar cells with the same origin that work together to perform the same function.
