Question

animal development
directions: read the sentences. put the steps of the growth process in order by writing 1, 2, 3, 4, or 5 on the line in front of each sentence.

1. ___ the egg and sperm unite.

___ cell - differentiation occurs.
___ an embryo develops.
___ the zygote divides many times.
___ a zygote is formed.
directions: unscramble the word in parentheses to complete each sentence.

1. a young insect is called a ____________ (nymph).
2. a kangaroo is an example of a ____________ (marsupial).
3. the ____________ provides food and oxygen to an embryo. (placenta)
4. the ____________ protects the developing embryo. (uterus)
5. young mammals feed on ____________ (milk).
6. most ____________ do not lay eggs. (mammals)
7. a ____________ has only one cell but a complete set of chromosomes. (germ)
8. when cells multiply, ____________ is copied in each cell. (dna)
9. a(n) ____________ is an early stage of an organisms development. (embryo)
10. when cells take on different ____________, cell - differentiation occurs. (jobs)
11. human embryos get ____________ from inside the mothers body. (food)
12. a caterpillar changes to a ____________ during its metamorphosis. (pupa)

directions: answer each question with a phrase or sentence.

1. what is gestation time?
2. how do gestation times compare among mammals?

Explanation:

Step1: Order the growth process steps

1. The egg and sperm unite.
2. A zygote is formed.
3. The zygote divides many times.
4. An embryo develops.
5. Cell - differentiation occurs.

Step2: Unscramble words

1. A young insect is called a nymph (from "gmyno").
2. A kangaroo is an example of a marsupial (from "ayrmasuil").
3. The placenta provides food and oxygen to an embryo (from "acenpta").
4. The uterus protects the developing embryo (from "utuesr").
5. Young mammals feed on milk (from "iluk").
6. Most mammals do not lay eggs (from "mamlmas").
7. A germ has only one cell but a complete set of chromosomes (from "gryoe").
8. When cells multiply, DNA is copied in each cell (from "DAS").
9. An embryo is an early stage of an organism's development (from "eyombr").
10. When cells take on different jobs, cell - differentiation occurs (from "bojs").
11. Human embryos get food from inside the mother's body (from "dofo").
12. A caterpillar changes to a pupa during its metamorphosis (from "uppa").

Step3: Answer questions

1. Gestation time is the length of time between fertilization and birth.
2. Gestation times vary greatly among mammals. For example, some small mammals have short gestation periods (a few weeks), while large mammals like elephants have very long gestation periods (about 22 months).

Answer:

1. 1. The egg and sperm unite.
2. A zygote is formed.
3. The zygote divides many times.
4. An embryo develops.
5. Cell - differentiation occurs.
6. nymph
7. marsupial
8. placenta
9. uterus
10. milk
11. mammals
12. germ
13. DNA
14. embryo
15. jobs
16. food
17. pupa
18. The length of time between fertilization and birth.
19. Gestation times vary greatly among mammals. For example, some small mammals have short gestation periods (a few weeks), while large mammals like elephants have very long gestation periods (about 22 months).